What's New


Cost of Trike Plans Have Been Drastically Reduced!

This economy stinks!!!  Inflation is widespread, cost of food, housing and durable goods have increased dramatically without increase in pay.  So until this sucky economy gets better I am lowering the price of my trike plans from $35 downloaded to only $25!  Trike plans on CD are also reduced from $40 to only $30.   Take that economy!!!!!!


Home Brew

Recumbents and beer have this really close relationship.  I have been home brewing now for over 6 years and have gotten really good at it (I've also gotten really fat too).  Not to be outdone by anyone I have built two kegerators; one is a dual tap and the other has four taps giving me a total of 6 beers always at my convience.  

On tap:

Oatmeal Stout, 5.3%

Wiezenbock, 7.2%

Chimay Dubbel clone, 5.9%

Chimay Doree clone, 3.8% ABV

Pale Ale, Sierra Nevada clone, 5.9%

Mexican Lager (with Agave extract), 4.4%



My Update Here In Raleigh NC

As some of you know, I was a member of Amazon’s NPI (New Product Introduction) team in Cupertino CA designing automated test systems for their Kindle products.  My new automated system was a smashing success and had saved Amazon 3.8 million dollars in capital equipment expenditures in the first year alone.  Suddenly I am working these long hours and making countless trips to China.  After being turned down for a promotion, I figured it was time to move on.  I get a fortuitous solicitation from a small company in Raleigh NC, they need a Hardware Test Engineer.  After a couple phone interviews and an in-person interview, I am offered a job that include moving expenses.  So in December 2012 I move 3,000 miles to start a new life and career in Raleigh NC.  Everything feels good; I buy a house and move my wife out here, things are going to plan.  After getting settled in and being employed for 3 months I finally submit my moving expenses where I expected to be re-imbursed for $6000.  That is when everything went south.  First, the company owner started complaining that he didn’t like how I was doing my job, telling me I had no initiative.  Next, he changed my contract on my moving compensation by adding a clause that I would be liable for a 20% penalty if I left the company before two years whether voluntary or not.  When I refuse to sign it, I was fired.  I was there for a little over 4 months.  I can’t tell you how demoralizing this is.  In California I could have sued him for every last penny, but in NC I didn’t have a leg to stand on.  Since then I had a four month engineering contract, but I still have not found any work out here.  If things do not improve I will be moving back to California.  This dream has turned into a nightmare.  

So please accept my apology for not making regular updates.  I am going through a rough time. Hopefully something good will happen soon.



I purchased a Spitfire from a former customer.   I now have two trikes in my stable; a ST20 and ST24.  More interesting is that the ST20 was the first production Spitfire, while the ST24 was the 2nd to the last made. 



It's Been a Long, Long Time...

Folks I apologize for my absence, but my real career as a Manufacturing Engineer for Amazon has been very demanding since the success of your debut tablet, Fire.   As expected, we are developing new hand held tech candy which we can expect to release in the near future. 


Site Changes Coming Soon

To best optimize my spare time, I am now only spot check my message board.  If you have important matters concerning your plans, please email me.  I do not have time to compose a long winded thesis, but I can give you quick answers.  To better serve my customer base, I will be building a new page dedicating to errata.  As this is much easier than changing the plans, bumping up the revisions and sending out gigabytes of emailed updates.


Spitfire ST24 For Sale 


I have purchased the trike below.  She is absolutely gorgeous and makes an excellent Birthday gift for my sweetheart Jude.  When I recieved, reassembled and adjusted the machine for Jude I forgot that that there were so many adjustments to make.  On the maiden ride, the toe-end was too strong and the angle of the u-bar forced the arms back too far.  The seat sling was too tight not allowing a decent cup on the bottom.  All these misalignments made a bad first impression on this fine machine.  However, after several adjustments and test rides, the trike transformed into a machine that matched its good looks.  Jude really like her new toy!


I have an old customer that has a low milage ST24 for sale.  This is a really super good ride and top shelf components.  He is offering it for sale for the low price of $2,495.  I have already offered him a deal for an undisclosed amount if this beauty doesn't move. So this deal is good for only 2 weeks.  After that, it's mine!!!!  Details of this trike are below:


              Only 100 miles on trike


              UT orange with Long Horn decals


              RS upgrades include hollow pin chain and XTR rear derailleur


              Options include:


             Both left and right rear view mirrors with bottle mounts


             Fenders, front and rear


             Rear brake


             Rack with Panniers


             Cycle Computer


             Lights, front and rear


              Shimano XT RD-M570-


              Shimano Ultegra


              SRAM 9 speed twist grip shifters


              Shimano Ultegra   FC-6503, 52/40/30


              Shimano Ultegra BB6503


              XT CS-M750, 9 speed, 11-32 range


              Velocity AeroHeat 36 Spoke, black w/machine side walls, ISO 406, 38mm wide Rims, 14 gauge black SS spokes, Velocity 20mm axle, Disc Brake  hubs


              Velocity AeroHeat 32 Spoke, ISO 518 Rims, 14 gauge. SS spokes, Velocity 9 spd cassette hub


              Front tires -Primo Comet 20”x 1.35”


              Rear tire- Panracer Technova II, 24”x 1-1/8”


              SRAM PC89R 3 9-speed


              Single chain roller on active side, Teflon tubing for passive side


              All components are high end Shimano Utegra or better (except for SRAM shifters and Hope Mini discs)


             Length =~80” 


             Width = 35.5”


             Wheel base = 40”


             Wheel Track = 31.5”


             Turning circle = 17.0 ft


             Weight (w/o accessories) = 30.7 lbs


             Capacity = 250 lbs


             X-seam= 37"to 47"






Updated Resource Page

My resource page is showcasing the hard work of Douglas Skidmore.  Although I have not received an essay yet, I did get a few photos worthy of placing on the Resource Page.  Please take time to check out Douglas's project.


'Free on Three' (Steven Greene, Trike Asylum)

Last year I was given an invitation to contribute to a book dedicated to recumbent trikes.  The book was being authored by Steven Greene of http://trikeasylum.wordpress.com/.  Although I never got around to contributing to this compilation, I did purchase a copy of 'Free on Three' for the Amazon Kindle.  For those interested in recumbent trike culture, this is a worthy read that goes beyond the technical bounds of my trike primer. 


Recumbent Trike Primer Next Generation

Free on Three has inspired me to take my trike primer to the next generation.  As always, this document will be free to the public.  However, I am requesting that people assist or steer me on technology to include in this document.\


Amazon Announced Three New Kindles

As many of you know, my real job is working for Lab126, which is the 'Skunk Works' division of Amazon.  My primary function is defining test methods and designing fixtures for evaluating the performance of our Kindle e-readers.  It has been an absolutely busy year for me, as supporting these projects to fruition has been a monumental task that has required countless trips to China and many late hours in the office.  These strenuous demands have diverted much of my resources in recent months.  However, I am relieved to say that the worst of it is over, at least for now and I am looking forward to spending more time with my personal passions, like recumbent trikes.



Unchanged Front Page

A reader commented to me that my webpage was last updated on 10/09.  It appears that I have to indexes; index.html and index.htm.  For the last two years I have only updated the .html index.  I have now fixed this and now maintain both pages.  I apologize for any confusion.


Show Case Your Thunderbolt Project

I have read several journals of people building this Thunderbolt trike project, but only received a few photos.  If you have completed your Thunderbolt trike and would like to show case it on my website drop me an email at trikesrcool@yahoo.com.  Images, journals or even links are welcomed.



Happy Holidays from Hellbent
Seasons Greetings to all of you.  2010 was another tough year for many of us.  As a Manufacturing Engineer, I've seen most of our core manufacturing move to Asia in the last couple years. You can blame it on the unions, on over-regulations, heavy taxes, or on our litigation system, but don't blame it on the American work force, we are and will always be a force to be reckoned with.  All I ask is that we buy locally whenever possible.  For those still looking for work, my heart goes out to all of you.


New Knuckle Bulkhead Reinforcement Blocks

Back In August I gave a design retrospective on the production Spitfire.  I concluded that the reinforcement plates for the bulkheads we not strong enough for riders over 220 lbs.  I designed a reinforcement block that now makes these bulkheads bullet proof.  These drawings have already been included with version 1.2.1 which was released in September.  If you have a version prior to this, email me and I'll send you the update absolutely free.


Yes, I'm Still Here!

I don't recall ever leaving my site alone longer than six month, so I'm setting a bad precedence.  Honestly, there isn't anything news worthy......wait, that's not true. 


The Spitfire ST20 after 6 years, a Design Retrospective

In July I purchased back a Spitfire ST 20 from the original customer who purchased it from Hellbent Cycles Inc back in 2004.  So this trike is roughly six years old and had logged many miles (I honestly don't the exact mileage).  So when I got it back I inspected every bearing, every mechanism, and frame tube for wear or damage.  Before I continue with my report, I need to explain the condition of this trike before it was sold to the previous owner.  When sending the frame back for powder coating I discovered a stress crack on the cross member.  I made the decision that this trike would be used strictly for demos and experimentation.  While on a contract job (trike building doesn't pay the bills), my business partner reinforced the cross-member tube to ensure that it would not fail.  Unbeknownst to him the new welding annealed the rest of the tube making it soft.  Keep in mind that I used .058 wall tubing for this complete trike.  This trike was eventually sold as a damaged demo unit. 

Fast forward July 2010, I caught second hand smoke that someone was selling this trike at an obscenely low price of $1200.  I mentioned to everyone that $1200 didn't cover the cost of components and quickly called the guy up and purchased it.  Eventually it was dismantled and shipped out to Cupertino.  So these are my findings.


Tires, worn to the cord, at least 2nd set


Wheel bearings- all appear to be in good condition


Disc brakes - pads have little wear, rotors look good with minimal ridge wear.


Chain idler - good shape, bearings fair, axle straight but loose in the frame (jam nut not fully secured)


Knuckle rod-ends - wear is minimal, these bearings are made of 7075 aluminum


Steering mechanism - acceptable play in the plain bearing used for the U-bar.  Steering point block that mounts to the knuckle lever exhibits play when steering is at the left extreme. This turns out to be a design flaw that does not account for a shear force at this orientation.  


Chain - No measurable amount of stretch was detected, but the sides of the chains links appear to have excessive to the point where the edges are sharp.  Although original brand, it is unknown if this chain was replaced.


Chain Tubing- Appears that this customer did his own custom work to the chain tubing.  The original PTFE Teflon chain tube had been replaced with polypropylene tubing secured using tie-wraps instead of the cable supplied with the trike.


Frame condition - all welds appear good, no cracking found


Cross-member - Tube appears to be buckling from annealing when the first repair was made.  This makes the front sag by .5". Knuckle Bulkhead - This frame component is under-designed.  Under maximum weight load the bulkhead starts to yield.  This can be rectified by creating an 1/8" thick reinforcement block (Steel) that is placed behind the bulkhead where the rod-end bearing is secured using a nyloc nut.  Although a much more elegant permanent solution can be had, the Thunderbolt/Spitfire are both at the end of their useful design.

damage to the knuckle bulhead is shown here

Note how this bulkhead is bent.  The cracks are only the powder coating (thank god!)

I have a drawing for a reinforcement plate (in place of the washer) that will prevent

this from occurring.



Seat and mountings - At first inspection the only sign of wear was a couple of holes in the seat sling where the fabric interface with the sharp edges of the double jointed hinge (This is something unique with the Spitfires; they had a adjustable seat back and the seat could be folded forward to reduce space).  I also discovered that the seat foam head rest was worn out (cost $4 to replace).  After making the necessary repairs I went for an extend ride to see if I could exploit any latent defects I missed.  While pulling myself up against the rear of the seat I heard a load bang!  This couldn't be good and my gut was telling me that I broke something that was going to more tan bailing wire to fix.  As it turns out, the hinge on the seat unglued.  A careful inspection revealed that the previous owner had run into this problem too.  To fix it once and for all, I'll glue (JB weld) / drill hole through both hinge and seat tube and insert a roll pin.


Riding Experience

My personal preference has always been the joystick steering mechanism, so I do have a bias.  Many years ago, BROL did a review on our ST20 and one key issue they had was the placement of the U--bar.  The handle grips were situated on each side of the rider at the belt line.  At the time, I never had an issue with the U bar handle placement, but now that I am 6 years older and have a much larger torso and arms, the placement does bother me.  So, next week as time permits I am extending the bar ends another 4" inches and see if that improves.

As I mentioned, its been a long time since I have been on an ST.  Due to a recent knee operation, I have diverted most of my running and cycling exercise to weight lifting.  I've gone from 175 lbs to 210.  This weight is at the high end of this trikes capacity, especially with the condition of the crossmember.  So, I'll need to loose 20 lbs before this machine will fit like it did.


Lessons Learned

In my idle time I have been exploring new designs ideas.  The most important is the steering knuckle configuration I currently use.  This configuration is excellent for those wishing to tweak their front end geometry.  However, the price for having this adjustable geometry comes at a steep cost.  Going forward I am going to use the standard bicycling steering tube and headset as most manufacturers have done.  I may option to go with an adjustable gimble system that allows the steering tube rotational adjustment for setting camber.  Obviously there is a cost and weight penalty, but as mentioned this is only optional. 

Although the under-seat steering has many fine attributes, I would go back to using direct coupled steering.  It's simple, light and is brutally effective.


Gusset reinforcement is a necessity.  For the Spitfire and Thunderbolt Mk II I used tube gussets, but these are extremely difficult to weld are heavy.  Internal type tube reinforcement is only partially effective.  So I'm going with a web type gusset, as these offer the best overall strength to weight ratio.

Overall I'm satisfied with the reliability of the Spitfire  I've known the steering knuckles and bulkheads were going to be the weakest part of design.  So it should not be a surprise to read that the Spitfire Mk II or Thunderbolt MK IV will use a more conventional steering system.


HPV Fun Day and Races 

Every year Carole and George Leone put on an event at the Hellyer Park Velodome. This year we donated first place prizes of home-brewed Ale and homemade breads.  For photos of this event, CLICK HERE. 



The Hellbent Recumbent Trike Design Primer Ready For Download!!!

As I mentioned last week, my key objective was to provide a badly needed update to my Trike Design 101.  Previously, this document was a hodgepodge compilation of shop notes, that was loosely written and dire need of updating and re-editing.  I'm proud to say that this has been completed, renamed, and uploaded for free release as an Adobe Acrobat PDF file.  The file link resides in the Resource section of this website, but you can save time and download it here.   Please enjoy!!!!!


Spitfire Interactive Experience

For over 4 years now I have had my Spitfire Mk II 3D design model posted on this website using an E-drawings plug-in.  This browser plug-in allows you to rotate, pan, zoom and concentrate on any aspect of this trike.  For those interested in building the Thunderbolt Mk III, this is an excellent tool as the geometry is nearly identical to that of the Spitfire Mk II.  Anyway, click on the Spitfire OSS, or Spitfire USS    



Happy New Year!!!

Folks, I apologize for not keeping all of you up to date.  I was recently laid-off from SGI and have been enjoying a long needed vacation.  As I mentioned on my message board, I want to dedicate some time in revising my Trikes101 primer.  As some of you may know this document has become the bible of recumbent trike design, and was used as the baseline for many successful trike manufacturers, including Catrike.  For the last several years Paulo has continuously perfected his trike design making them a force to be reckoned with.  In the meantime, my trike primer was been left neglected and in dire need of updating.  So expect many great changes to this document.


I also would like to thank all my customers for making 2009 a successful year.  Although I have lowered my plan prices and substantially added more details, sales have lately been disappointing due to our softening economy.  So I am going to continue keeping my Thunderbolt Mk III plans at the introductory price until the end of this year.  Hopefully our economy will pick up by then and I'll have another design to offer.



Under Seat Steering U-Bar Mechanism for The Thunderbolt Mk III Plans

I have had a few customers requesting me to release a conventional Under-seat U-bar steering mechanism for my plans.  As some of you know, I did offer a U-bar for my Spitfire ST.   Although functional, the mechanism was complicated and difficult to build.  If anyone is interested, please contact me for drawings and instructions.  I will not be adding these drawings and documents to the released instructions until late October. 


I'm Hell-Bent On Home Brewing

As some know, my passions are designing recumbent trikes, running and cycling.   However, after blowing my knee out last year and subsequent surgery, I have turned my attention to making beer where I have made over 120 gallons (454 liters) and have mastered it to near perfection.  In fact I have recently won four 1st place and one 3rd place ribbons at two Home Brewing Contest (Alameda and Santa Cruz County).  So as it is now; beer, building, and blondes.  More to come shortly.



Steel Red-Lines Available

The drawing red-lines for making the Thunderbolt Mk III out of steel are now available.  For customers who purchased the Mk III plans these red-lines are free.  Please contact me at trikesrcool at yahoo.com for downloads. 


All subsequent Mk III plans will include these redlines as version 1.1 of the plans


Mk III Upgrade for MKII 20 Customers

Customers who purchased my Thunderbolt Mk II 20 plans can upgrade to the Mk III for $12.50 through Paypal.  Contact me so that I can steer you to the correct link for purchase.



Make A Thunderbolt MK III Out Of Steel!

Both Spitfire and Thunderbolt Mk II/III were initially designed for aluminum construction.  However, most homebuilders do not have the equipment or expertise for welding aluminum.  So, I'm losing a lot of business out there.  The saving grace is that a steel version of this project can be built.  Not only does this simplify the building process, but it can still produce a world class world class trike.


First, let me explain the properties of carbon steel and how it compares to aluminum or Cro-Mo. Almost all steel has a percentage of carbon; the more carbon the harder the steel. However, too much carbon and the steel becomes brittle. As I previously mentioned, I used muffler pipe last year and found it extremely soft. Well it turns out that 1010 steel is slightly stronger than aluminum, but weighs 3x as much. This means a trike made from this crap will be 16 lbs heavier, not acceptable!! So, I discovered that the higher carbon 1020 and 1026 steels were much harder, with the 1026 variety coming within 5% of the strength of CroMo. So, as a happy medium, I am specifying 1020, as anything harder is going to be too hard to bend.
bulletThe Main and cross-member tubes are specified as 1.75" OD with a .049" wall.
bulletThe BB tube is specified as 1.625 OD with a .049" wall. With all tolerances, this be an excellent fit after painting.
bulletThe sheet-metal bulkheads should be fabricated from 12 gauge, grade 30 sheet-metal steel. If grade 50 is used, the thickness can be reduced to 14 gauge. CAUTION- with the reduced diameter of the cross-member tubing the bulkheads will need to be changed accordingly.
bulletThe pinch collet and pulley mount will be made of 7/16" OD with a .083" wall. This size makes it easy to tap a 5/16-24 TPI thread
bulletAll seat tubes (yes, even the back tube) should use 5/8" OD tubing with a .049" wall. Again, this reduced diameter keeps the weight down.
bulletThe stays and drop outs are off the shelf components that can be purchased from www.fairing.com or from www.novacycles.com
bulletStays example http://www.novacycles.com/catalog/product_info.php?cPath=35_271_272_273&products_id=1522 These tubes will be used for both chain and seat stays.
bulletDrop out example http://www.novacycles.com/catalog/product_info.php?cPath=25_114_119&products_id=875
bulletSteel Bottom Bracket example http://www.novacycles.com/catalog/product_info.php?products_id=1500


Two 1" diameter x 3" long cross-member tubes (1" OD with a .049" wall) are required to accoRear Sectionmmodate the stays, refer to the drawing below:

 Furthermore the ovalized stays may require rounding to accommodate this cross-member, as they are almost 1-1/8" wide.

Gussets are not required for steel construction, so although using steel almost doubles the weight, the absence of the gusset should help this handicap.

In the meantime, I will contact the Tube Service for pricing and availability. If I get enough interest, I'll offer tubing for sale. So far I have only two people interested. When I get 10, it might be worth my time.

This should get everyone started. I will be updating this list weekly if not daily until I have everything nailed.

As for making formal changes to the drawings, Absolutely NO. At this time I'm only redlining these drawings. The formal changes will be incorporated when I increase the price of the plans (I wasn't kidding when I said this was a limited offer). However, the price will remain at $35 until the end of July, perhaps even August.


Introducing the Thunderbolt Mk III!

I understand that this economy really stinks.   For those of you working, we are doing so with reduced income or too scared to spend the little money we have.  So to remedy a bad situation I am now offering a fantastic deal.  For a limited time I am selling both Thunderbolt Mk II 20 and 26 plans for an insanely low price of only $35.00!!!!


.......BUT WAIT!!!!!!!!!


Not only am I simply lumping both plans together, I have also updated the Mk II 20 plans so they now have the same feature levels as my 26" plans.  Again, both complete plans for only $35.00


......THAT'S NOT ALL!!!


Not only do you get an updated version of the Mk II 20 along with the Mk II 26 plans, I am also including plans for a segmented frame and have revised almost every drawing and every chapter to ensure these plans have no equal.   Imagine, you can build a world class trike that can be dismantled and placed in  the trunk of a car!  All this for the low price of only $35.00.   To read more about these plans, CLICK HERE




Steel Rear Section Design for Thunderbolt Mk II 26

A common question I receive is, "Does your design allow fabrication from steel?".  My answer is always 'yes'.  However, a couple caveats need to be addressed.  First, most aluminum designs include larger diameter tubing that offers greater stiffness.  This stiffness helps reduce flexing which will eventually lead in metal fatigue.  Alloyed steel has less of a propensity for fatigue, so these tubes can be smaller and springier.  Hence, the rear stays and dropouts for a steel frame differ in size and shape from their aluminum counterparts.   Secondly, the joining of these steel stays to the Main Tube section of the frame also differs.  Representing a steel rear section deserves a bit of ambiguity, so I have created a baseline drawing that appears shown below: 

Rear Section

The actual geometry is almost identical to the aluminum version, with the exception of the two bridge tubes.  This example above is from the Spitfire Mk II 26 rear section design which is made from two sets of chain stays that can be aluminum or steel.  I should have these sketches quantified and available in a couple weeks for the Thunderbolt Mk II 26.  If you that have purchased the Mk II 26 plans these sketches are free.



My Day Job Puts the Trike Project on Hold

Some of you may have noticed that I am not responding as quickly to my emails lately.  I've been so busy with work, that I don't have time to devote to my trike project.  As an NPI (New Product Introduction) Engineer my responsibilities include designing new manufacturing tools (electrical, mechanical, and software) for our contract manufacture in Holland.  Not only will I be designing new tools, I will also be traveling abroad to Europe over the next couple months. Consequently, I've placed my project on hold until the fall when I will have more time to devote to it. 


WWW.GotTrikes.com Has a Solution for Your Thunderbolt Steering Projects 

I am placing another plug for Frank Takacs for his beautiful machining talents.  Frank not only is an excellent machinist, he is also an accomplished Designer/Engineer as well.  Next week I'll include a few more photos of his handiwork. 



Hip Hop to the Tech Shop!

I got a late start in getting this class rolling, as I could only find a single, local volunteer to join me.   To save time and money, I am planning to build much of this project from steel.  Yes, this is a drastic departure from all my other aluminum designs, but I believe much of my customer base would be more comfortable fabricating a tricycle out of steel rather than exotic aluminum.  Although changing from aluminum to steel requires different tube diameters and thicknesses, the geometry will remain the same.  Expect a living diary on my Resource page. 



Last Production Spitfire ST24 is Sold

The trike was sold on eBay very close to the amount asked.  Appears ol' Todd can now afford a pair of new shoes for that baby.


Last Call To The Tech Shop

Back in 2003 I offered an outstanding deal on a set of Velocity Wheels at 5% above OEM cost ($50.00 ea).  I didn't have a single buyer.  Months later, several people were e-mailing me asking if that deal was still good.  Of course I replied it wasn't.   I also offered a free course in trike building using my own shop resources, again no takers.  So here I am again offering a free class (you have to be a member of the Tech Shop) with no takers.   So to sweeten this deal, I am now requesting all interested participants donate $150 to the American Cancer Society upon the completion of their project ;-).  


Frank Takacs At www.GotTrikes.com Has Thunderbolt Parts For Sale

Frank sent me an email with a lovely photo of some steering knuckles he fabricated.  Frank's attention to detail and quality really show.  If you need parts machined for your trike project, see Frank.   

Frank's Knuckles above sell for $80/pair


These are updates from an earlier posting

Original Spitfire Building Jigs for Sale

We are selling the remaining Spitfire ST/RS Jigs and misc. parts.  These jigs allow the critical frame alignment to build a Spitfire trike.  There are several of these fixtures and all are in excellent working condition.  As part of this offer, the sale entitles the buyer to build and sell unlimited trikes under a restricted agreement.  Last, the deal includes several parts including tires, rod-ends, etc...  For more information follow this link.  


Last Production Spitfire ST24 For Sale

This is the last production Spitfire made.  The frame was built for our welder.  He was building the trike, but never finished due to a new baby (The baby was more time and money than he thought).  The trike is 98% finished and has 0 miles on it.  All that is needed to finish is a seat made, mount chain, hook up shifters and align the front.  Plans for the seat are included in the sale.  Below is a photo:

                                        The ST24 shown with the seat adjusted to the upright position

The only difference between the production trike is this one has mechanical disc brakes instead of hydraulic.  The frame has a beautiful purple powder coat finish.  $2450 plus shipping.  I last want to mention that the ST24 was our most popular model.  For more information about the Spitfire, click here.    Call Todd at 512-517-7071.



Spitfire vs. Thunderbolt Mk II

Several readers have asked me what the differences are between the Spitfire and Thunderbolt Mk II.  In a nutshell, the Spitfire is a production trike that was/is built  by Hellbent.   The Spitfire uses several OEM parts and has subtle features (variable reclining seat, bottle mounts, heli-coil pinch collets, etc) that are not included on the Thunderbolt Mk II plans.  Although subtle, these differences provide a contrast to maximize the investment of current Spitfire owners. 


As mentioned, I am planning on building a modified design in April.  Although I will dub it as a Spitfire, the planned version will be called a Thunderbolt. 


An interesting BROL article on the VeloKit

I found this review very interesting and noteworthy.  The VeloKit is a light weight enclosure that can be mounted on a wide variety of tadpole trikes.   Read the article on BROL for more information.  



We Morn a Great Loss

Last week I discovered that Sheldon Brown had passed away.  For those who do not know Sheldon, he was one of the greatest bicycle gurus.  It was Sheldon Brown who gave me his unbiased and humble advice when I was struggling designing my second generation Zephyr back in 1994.  Although not a avid recumbent cyclist, Sheldon kept a keen interest in recumbent technology and was a key contributor to the IHPVA recumbent news list.  Modest, brilliant, and personable are just a few adjectives that describe this great man.  I can go on for days trying to list all the terrific things about this guy and I would still overlook a few.  I am lost for words- I will sincerely miss you Mr. Brown! 


If you have never visited Sheldon Brown's website, I strongly suggest doing so now.  http://www.sheldonbrown.com/home.html


Building a Trike at the TechShop

I'm still looking for San Francisco Bay Area volunteers interested in joining my trike building class using the resources at the Menlo Park, CA TechShop.  The Techshop is a public work shop that has all the equipment needed to build a Thunderbolt trike.  The shop fees are $100/mo.  Please refer to the website for more information.   All volunteers are entitled to a free set of Thunderbolt Mk II 20 plans.  Materials are extra.  I am hoping to get this started before May of this year.  If interested, contract me, Rick at trikesrcool@yahoo.com




Happy New Year

First, I want to thank all of you out there that have been instrumental in making this website a success.  I took an extended hiatus for over a year and had almost let this site go to waste.  I credit my girlfriend Jude, who insisted that I give it another chance. Well when I did I immediately fell in love again and I started writing.  For her great support I will be building her a new Spitfire Mk II along with another which I plan to donate to charity. 


RCN is gone - Viva Recumbency!

Bob Bryant throws in the towel after 16 years as editor and publisher of Recumbent Cyclist News.  Someone stated that his circulation had dwindled down to 1,000 subscribers?  This only proved that RCN had become totally irrelevant in the new recumbent industry.   Regardless of this callus jab to Bob Bryant, I do sincerely wish the Bryant family all the best.  After all I’ve always been blessed with many marketable talents that have allow me a rewarding career and hope Bob’s transition back into the workforce proves to be both prosperous and dignifying. 


For 2008

As I mentioned before, I got my mojo back so watch out!!!!!!!!  I've got some heavy duty stuff in store for 2008.  First, I'm going to finish the design of the Spitfire Mk II.  Next, I am searching for local volunteers (San Francisco -South Bay area)  who would be interested in building a such a trike. I discovered a shop in Menlo Park that allows access to their machining and welding equipment for a reasonable fee.  My intentions are to provide a free class on building a recumbent trike (Spitfire Mk II).  My take in the action is documenting the process from beginning to end.  Drop me an email if interested.     



Resource Page is filling up

I'm finally finding the time to add all my links to hard to find resources.  I have several more links to include, but I need to organize it better.  In all things are looking really good.  Check out my resource page here.



Builder's Support Forum is up and running!

Do you have questions about building your trike? The new Builder's Support Forum is now operational.  Click here  



As Promised

I wish to thank my former customers for their support in helping me with my partnership issues that started 2 years ago.   As promised I have sent each of you a free copy of my new Thunderbolt Mk II 26 trike plans.   If I missed any of you, please email (trikesrcool@yahoo.com)  as some e-addresses were no longer valid.

 As a footnote, the last two years have been difficult for me to get back into pursuing my endeavors in designing and providing plans for recumbent trikes.   I have thought several times on shutting this site down, as I totally lost my passion and desire.  However, with my renewed interest, I have vowed never again to go back into business as a trike manufacturer, but instead will be using the proceeds of my trike plan sales to fund the research and design of recumbent trikes.  I plan to build a few trikes next year with one trike already being donated to the American Cancer Society.  Therefore, there will always be a few new Hellbent trikes out there, but none will be for sale from Hellbent.     


Forum Proposed

I have had numerous request from people asking for a builder's support forum.  I've never set one of these up.  If there is anyone that can suggest which software package to use, please advise.




Thunderbolt Mk II 26 Plans Now Available

As promised the plans for the Thunderbolt Mk II 26 are now available for sale!  Click here for details



Thunderbolt Mk II 26 Status

As mentioned in an earlier statement, Spitfire XX26 development is currently on hold due to high cost in prototyping.  As an interim solution, I am releasing the Thunderbolt Mk II, 26.  This version of the Thunderbolt sports a 26" rear wheel and a slightly modified seat (has a lumbar bend).  The design is similar to the ongoing Spitfire design, but it will not be offered in 3D modeled drawings (except a few parts).  Price is set at $45.00 for the downloaded version.  This design will be ready for order on 11/18/07.  The preview is shown below:


If anyone has further questions, please contact me at trikesrcool@yaoo.com




Offering Parts For Sale?

Again, I am contemplating on offering parts for sale.  Machined parts will be the first offered, followed by prefabricated (cut and formed) frame tubes.  If successful more items will follow.  If you are a machinist and interested in making some walk around money, please contact me at trikesrcool@yahoo.com   



Hellbent will be accepting online Credit Cards and PayPal!

This is big news for me.  With the American dollar at an all-time low, my T'bolt MkII plans are becoming increasingly popular abroad.  However, to keep prices low I previously avoided accepting credit cards and PayPal, which became a burden to my valued international customers.   Not only does the acceptance of online credit cards expand my business horizons, but it also demonstrates my continuing commitment in designing and releasing new trike plans.  Unfortunately,  I'm also faced to make some adjustments to pricing. 

Starting this 10/19/07 the following prices apply:



Thunderbolt Mk II plans (downloadable version) remains at $25.00 USD.


Thunderbolt Mk II plans on CD will increase to $30.00 USD.  CDs shipped outside of the USA add another $5.00 USD



Wrong Address!!!!

Oops!  I posted the wrong mailing address for my trike plans.  The address should be:


10056 Pasadena Ave, Apt. B

Cupertino, CA 95014


I know this is a repost as shown correctly below



Lost Request Finally Delivered

I received a handful of complaints from customers indicating that they never got their plans.  Blame it on the US Postal System for delivering me forwarded mail two months old.  The plans will be sent immediately.  In the meantime I apologize for the delay.  Remember my new address is:


10056 Pasadena Ave, Apt. B

Cupertino, CA 95014



Company Status

Regardless of any circulating rumors, this site and company are very much alive. I have a very aggressive schedule that includes a 50 hour + work week, not to mention  12 hours/ week for weight training and running.  Obviously, I don't have much free time left.  To put things in perspective; the Thunderbolt Mk II plans consumed over 300 hours to compose, this does not include the time for trike fabrication.   The drawings for the RS/ST26 took over 290 hours to draw.   However, much of this time was consumed learning how to use Solidworks.  

Anyway, I remain committed to this project.  I can't say when I am completing it, but I will say that it is a project that is still under construction.  It will be done.


New address:

10056 Pasadena Ave, Apt. B

Cupertino, CA 95014



Site Status

The proceeds from my Thunderbolt MK II plans cover the cost of this website and for some of my remaining legal cost.  Without sufficient funding, I have halted the completion of the RS/ST26 plans.  Honestly, I haven't built a finished prototype of this trike and it would be liability to release the plans as is.  In the meantime I am focusing my efforts on releasing plans used for the RS24, but with a 26" rear wheel.  Allow me to reiterate that my recumbent trike venture has always been a business loss and is strictly a hobby. 



Spitfire RS/ST26 Update

First, I apologize for not keeping this site current.  After settling my legal dispute I got burned-out on this trike business and took a much needed hiatus.  I am now back to work putting the finishing touches on the new Spitfire RS/ST26 design.  The drawings are the easy part and the daunting task of composing the detailed instruction is still a work in progress.


Some minor design tweaks are being made so that many of the parts such as the rears stays and drop-outs can be ordered preformed.  In addition I will be working with some frame component manufactures on having the seat preformed and cut, requiring only welding to complete.  The same applies for the frame main tube and cross-member.


The plans are tentatively priced at $49.00.  I will not accept any advanced orders at this time!  Depending on my financial situation, I may set up this site to accept credit card orders.  


Thanks for Your Support

I want to personally thank all the individuals who sent in their receipts for helping me prevail in my legal battle.  It certainly paid off and I am grateful.  I will hold my end of the bargain and apologize for not releasing these plans earlier.


Site Changes

I have upgraded my site to handle up to 5 gigabytes of data and some other features that will soon be announced.  Many changes are expected in this transition as I move forward.  Although my primary focus is providing recumbent tricycle plans, I may still offer frame parts and components for sale or provide links to businesses that offer them. 




Machinery Available For Sale

In anticipation of finally getting back my property from my ex-business partner, I have placed all my stuff on this website for sale.   The proceeds will go towards my legal fees and paying off debts incurred while in business as Hellbent Cycles Inc.   Click here to see the equipment.




Things just keep getting better!!!!!! I'm thrilled to announce that I have almost finished designing a revolutionary new Steering Knuckle design that allows a quick release detachment from the cross-member of the frame.  Best of all the design is very simplistic.  I hope to have the drawings completed in a couple weeks.  Upon completion, I'll send the drawings out to a couple of machinist so that I'll have a couple evaluation units to play with.  These knuckles will be part of the upcoming RS/ST26 plans.  Stay tuned for some awesome drawings.



Machinist Wanted

Over the last couple weeks I have received several requests amounting to over $3,400 for machined parts and tubes.  Unfortunately, I do not have a machine shop or equipment to fill these orders.  If anyone is interested in providing these services, please contact me (Rick) via email at trikesrcool@yahoo.com 


Components and Materials To Be Offered Soon

I am in the process of selling my intellectual property of the Spitfire 26 design.  The proceeds of this sale will be used to provide components and materials for my plans.    


Spitfire 24 Construction Plans

I am performing some ground breaking effort on composing plans for the upcoming Spitfire 24 Mk II.  This trike design will be much easier to fabricate and will be completely drawn in 3D-CAD. 



Clarification Needed

Hellbent Cycles Inc still exists, but not on my website.  



Hellbent Cycles Inc. Is Out! 

Our attempts to sell Hellbent Cycles Inc. was unsuccessful and I have exercised my right in retaining my intellectual property.   Consequently, Hellbent Cycles Inc no longer exist on this website.  I have reverted it back to Hellbent Cycle Works.  During the next few weeks I'll transform this site to focus more on home building projects.  Plans for the Thunderbolt Mk II will be available for purchase, but parts and accessories will no longer be available.  Stay tuned for more details.


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