www.recumbents.com - Do's & Don't's of Designing/Building a Speedbike
www.recumbents.com
www.recumbents.com
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
 All Forums
 www.recumbents.com
 Technical / Bike Building
 Do's & Don't's of Designing/Building a Speedbike
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

Adam C
recumbent enthusiast

USA
227 Posts

Posted - 03/12/2012 :  09:54:27  Show Profile  Visit Adam C's Homepage  Reply with Quote
I've read all the articles on the designing and building HPV's on this website. I wanted to ask everyone to share their other "secrets" and Do's and Don't's of building a fully faired speedbike.

Edited by - Adam C on 03/12/2012 09:55:21

Speedy
recumbent guru

USA
759 Posts

Posted - 03/12/2012 :  10:44:51  Show Profile  Reply with Quote
Do something even if it's wrong.
Every time I finished a bike the first thing that came up was :
this isn't right ... it should be done this another way
and that's with bikes that have gone on to win
Go to Top of Page

Speedbiker
human power expert

USA
2467 Posts

Posted - 03/12/2012 :  11:48:18  Show Profile  Reply with Quote
Right-O Steve. Build something! I suggest you don't try to reinvent the wheel. Many have done well with Varna clones, and for good reason.
Go to Top of Page

n/a
deleted

2373 Posts

Posted - 03/12/2012 :  12:02:12  Show Profile  Reply with Quote
Don't build a bike with a non adjustable or wide bottom bracket. Anyone who builds bikes with no BB adjustment has loose marbles in their cranium.
Go to Top of Page

Victor Ragusila
recumbent enthusiast

Canada
352 Posts

Posted - 03/12/2012 :  12:32:40  Show Profile  Reply with Quote
I disagree with AA about fixed BBs

The toe and heel clearances are the most important from an aero point of view. All our bikes so far had fixed Bottom Bracket (BB) that kept the toes and heels to within 2mm of the shell.

What we did to get the rider to fit well was make adjustable seats, with foam pads that we insert to get the rider in the correct seating position and at the correct distance to the BB.

I agree with AA in terms of making a narrow BB. This year we went with a 85mm Q-factor. Last year we had 100mm and it didnt feel too weird..

Victor
Go to Top of Page

Upright Mike
human power expert

USA
3463 Posts

Posted - 03/12/2012 :  13:17:48  Show Profile  Visit Upright Mike's Homepage  Reply with Quote
Build it small - smaller is better. DON'T LEAVE EXTRA ROOM!!
Georgi and Damjan said to a room full of us at BM 2010 to NOT leave an extra 1/4 inch, or extra mm. Damjan said to instead get out a sander and take material off the inside of the shell if you are rubbing somewhere with your heel, knee, etc.

A lesson I learn from making a streamliner for ASME - we gave ourselves about 2 inches of room all around our largest rider - big mistake - we had a fairing about 30 inches wide, which we nicknamed the "bus", because we probably could have fit two more people inside it.

Also - PRACTICE RIDING. I'm a firm believer that even if you have a crappy, semi-finished design that you can put all the power to the pedals with confidence, you will go faster than the person whose spent a 1000+hours sanding their slick fairing to a mirror finish (only to crash in their first run). Too many people do their first runs at Battle Mountain, crash, repair, etc. The teams that can get out and practice at an oval test track (there are plenty of them around), will do better.

LASTLY - get the gears and drivetrain right. You might have a perfectly detuned drivetrain, but then discover that your gearing isn't right for BM. Maybe you're spinning too fast making the nose bounce around and running out of gears (my problem) or you don't have a low enough gear to start easily (my problem) or you thought you were going to go 100 mph so put a monster gear in it then went nowhere.
Go to Top of Page

Victor Ragusila
recumbent enthusiast

Canada
352 Posts

Posted - 03/12/2012 :  14:45:33  Show Profile  Reply with Quote
to build up on what Mike said, race as much as you can. The summer IHPVA races are great to get more experience and fine tune and robustify your bike.

try to use off-the shelf drive train components. this way, you can swap chain-rings and cogs easily. try to do some calculations for the gear range you might need, and then make sure you can modify it to be at least 20% higher and lower.

also, make the bike the smallest GOOD aero-shape that fits you. I recommend "the leading edge" as a great reference for aero design. a small bike with a bad shape will be slower than a slightly larger bike with a great shape.
Go to Top of Page

jjackstone
recumbent enthusiast

USA
173 Posts

Posted - 03/12/2012 :  18:05:19  Show Profile  Reply with Quote
If you are planning on having a bike ready for any given year, DO start at least a year in advance. This MIGHT give you time for proper testing and modifying for the year race you are building for.

JJ
Go to Top of Page

Speedbiker
human power expert

USA
2467 Posts

Posted - 03/12/2012 :  19:47:01  Show Profile  Reply with Quote
My favorite advice is that if it is wider than 18", longer than 9', and has a primary fuselage height of more than 24", or more than 2 wheels, you may want to reconsider your design. And unless you have very good engineering, it should look alot like one of the bikes that has gone 70+. Unless you are from the future or another planet, stick to what is proven to work. You will have ALOT more fun. Just review past performances of builders who didn't follow these rules and see their lack of fun.
Go to Top of Page

Jeff Wills
human power supergeek

USA
1209 Posts

Posted - 03/12/2012 :  20:29:02  Show Profile  Visit Jeff Wills's Homepage  Reply with Quote
quote:
Originally posted by Speedbiker

My favorite advice is that if it is wider than 18", longer than 9', and has a primary fuselage height of more than 24", or more than 2 wheels, you may want to reconsider your design. And unless you have very good engineering, it should look alot like one of the bikes that has gone 70+. Unless you are from the future or another planet, stick to what is proven to work. You will have A LOT more fun. Just review past performances of builders who didn't follow these rules and see their lack of fun.



I'm 6-foot-4 and 22 inches across the shoulders. The only way I'm going to fit in that envelope is if I chop off my head and one arm. And then I'd really look like I'm from another planet.

Still, I'm aiming for BM this year. I want to see how fast I can go.

__________________
Jeff Wills
All my bikes:
http://home.comcast.net/~jeff_wills/Gallery/index.html
Go to Top of Page

Speedbiker
human power expert

USA
2467 Posts

Posted - 03/12/2012 :  21:10:15  Show Profile  Reply with Quote
I hate to tell you this, Jeff, but the Coslinger Spcl is smaller that what I described and both Dennis Grelk and Frank Geyer fit in there. Don't do a Queally and think you should rattle around in there. Standling relaxed I'm alot wider than the Cos' 17.5", but I have done distances of up to 100 miles in there. Obviously, exceptions have to be made for sizeable persons, but I stand by my rules. Do you want to go fast? Or do you want to spend a ton of time and money going slow?
Go to Top of Page

Dreamer
recumbent guru

USA
607 Posts

Posted - 03/12/2012 :  21:31:32  Show Profile  Reply with Quote
"Fun" means a lot of different things to different people. It might be fun for some to build a clone of an existing fast vehicle but, for me personally, "fun" is figuring out what makes each unique design fast and then understanding what keeps those designs from going faster. Finally, fun is to build a unique vehicle based on those observations, theoretical solutions, and personal goals and learning the skills to put it all together.

My advise if you really want to experience and enjoy the sport of building hpvs is to learn as much as you can and then design and build what turns you on. If that doesn't make you happy you can always build a clone.

I'm on my 5th build and probably more like my 10th design and the vehicle coming to Battle Mt'n isn't going to look much like anything that's been there before and any resemblance to previous vehicles is unintentional.

For me, that's the ultimate way of having fun. <G>

Don

Edited by - Dreamer on 03/12/2012 21:32:49
Go to Top of Page

Victor Ragusila
recumbent enthusiast

Canada
352 Posts

Posted - 03/12/2012 :  22:23:55  Show Profile  Reply with Quote
Vortex fits riders 6ft3. Are you anywhere around Toronto? We have the ACE and Vortex molds here, and if anyone is interested in the CAD shape or laying up a fairing using these molds, we can work something out.

ACE went 62mph, Vortex went 73mph.

Victor
Go to Top of Page

Larry Lem
human power expert

South Sandwich Islands
2302 Posts

Posted - 03/13/2012 :  08:24:42  Show Profile  Reply with Quote
Steady-state power always needs to be listed for speeds to be meaningful. We haven't seen Jeff Wills vehicle at BM yet, but using Warren's Cuda-W as a similar vehicle, if Todd, Sebastiaan, or Dennis were powering it, it might go 73 mph as well.

...now does Warren take offense that I think those 3 guys are stronger than him, or does he take it as a compliment that I think the Cuda-W is a wonderful vehicle?

Larry Lem
Go to Top of Page

Speedbiker
human power expert

USA
2467 Posts

Posted - 03/13/2012 :  09:33:01  Show Profile  Reply with Quote
I suspect that Warren would agree that Sebastian can out sprint him. He would probably not mind seeing what Sebastian could do in the Cuda, with a little more gear :-)
Go to Top of Page

warren
human power expert

USA
4902 Posts

Posted - 03/13/2012 :  17:56:32  Show Profile  Visit warren's Homepage  Reply with Quote
Ya, no offense taken. A tall young guy with time to train properly would certainly go 70+ in the 'Cuda. I never have been a sprinter, or had time to train properly for that matter.
Go to Top of Page

Jeff Wills
human power supergeek

USA
1209 Posts

Posted - 03/13/2012 :  21:18:57  Show Profile  Visit Jeff Wills's Homepage  Reply with Quote
quote:
Originally posted by Speedbiker

I hate to tell you this, Jeff, but the Coslinger Spcl is smaller that what I described and both Dennis Grelk and Frank Geyer fit in there. Don't do a Queally and think you should rattle around in there. Standing relaxed I'm a lot wider than the Cos' 17.5", but I have done distances of up to 100 miles in there. Obviously, exceptions have to be made for sizeable persons, but I stand by my rules. Do you want to go fast? Or do you want to spend a ton of time and money going slow?



Well, I don't know about standing around, but I'm a press-fit in the Cuda-W-2. If you take a look at the photos, you'll see that my shoulders push out on the rear of the lid, and my knees rubbed themselves raw last year. Obviously there's adjustments that need to be done, but I don't know if I can make the envelope much smaller.

I'm not looking to spending a huge amount on the machine (I'm married, after all), but I do want to see what she'll do. Going 50 before turning 50 is a reasonable objective- going 60 before I turn 60 might be possible.





__________________
Jeff Wills
All my bikes:
http://home.comcast.net/~jeff_wills/Gallery/index.html
Go to Top of Page

Speedbiker
human power expert

USA
2467 Posts

Posted - 03/13/2012 :  21:38:10  Show Profile  Reply with Quote
Dial it in, Jeff. Sealed up with a full canopy and that thing will coast 60! Maybe put some bolsters on the seat so it keeps you narrow.
Go to Top of Page

Speedbiker
human power expert

USA
2467 Posts

Posted - 03/16/2012 :  06:26:09  Show Profile  Reply with Quote
Is that a Chinese motorctcle ad spam? Crazy!
Go to Top of Page

W Hilgenberg
recumbent enthusiast

USA
285 Posts

Posted - 03/16/2012 :  07:39:41  Show Profile  Reply with Quote
But it is a cool bike. . .
Go to Top of Page

warren
human power expert

USA
4902 Posts

Posted - 03/16/2012 :  09:20:39  Show Profile  Visit warren's Homepage  Reply with Quote
cleansed...
Go to Top of Page

PUGZCAT
recumbent enthusiast

Canada
279 Posts

Posted - 03/16/2012 :  16:53:44  Show Profile  Reply with Quote
Hey Victor, it's hard for me to imagine a better velomobile than the U of T Vortex molded out of ABS plastic and a parallelogram tilting trike rear end with a tilt lock for getting in and out.
Go to Top of Page

Grant-53
New Member

USA
51 Posts

Posted - 03/18/2012 :  17:32:53  Show Profile  Reply with Quote
If you are not comfortable you are not going to be able to go fast. Temperature and air flow inside the shell is important too. You are your power supply. Keep a check list and note book as things get exciting in competition. Walk the course and take note of surfaces, reference points, sun and wind conditions throughout the day. The easiest person to outsmart is yourself.
Go to Top of Page

Speedbiker
human power expert

USA
2467 Posts

Posted - 03/18/2012 :  18:36:00  Show Profile  Reply with Quote
Sounds like Grant has raced cars...
Go to Top of Page

Grant-53
New Member

USA
51 Posts

Posted - 03/19/2012 :  07:30:54  Show Profile  Reply with Quote
I grew up racing slot cars and studied Mech. Engineering to be a Mark Donahue wannabe. Changed my mind afer a couple close calls. I started riding bikes at 6 yr. old on the cinder alley behind our house in Pennsylvania. Spent time around glider pilots. Now I design fairings for commuter bikes.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
www.recumbents.com © 2009 www.recumbents.com Go To Top Of Page
Snitz Forums 2000