jamestziros
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 posted on 17/1/06 at 09:21 PM |
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BEC Reverse Gear
Hi People
I am using a bike engine in my locost but still want a reverse option...!
I have heard the purpose built units for an actual reverse gear are not very reliable..and are expensive.. anyone had experience?!
The other option is to use a starter motor on to a gear on the diff drive flange, engaged the conventional way. Obviously I need to make sure it turns
in the right direction....!
Does anyone have any experiences or pointers on types of starters to use.
James
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lightspear27
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| posted on 18/1/06 at 08:19 AM |
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Hi,
(reply related to the topic in the link above)
Why not use a bike engine/gearbox in the engine bay + propshaft + transaxle gearbox (Alfa, Subaru, Citroen, VW, ...) instead of the diff?
It would certainly be lighter than bike engine/gearbox + prop + car gearbox (type 9 for example) + prop + diff!
Is there a good reason why it should not work?
Imagine an AlfaSud transaxle gearbox with inboard disc brakes at the rear!
Should be nice and good for weight distribution too.
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Bob C
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| posted on 18/1/06 at 12:27 PM |
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I did a combined electric reverse/ handbrake/ prop centre bearing - pics
http://freespace.virgin.net/bob.carter/images/trbrk.jpg
http://freespace.virgin.net/bob.carter/images/centbrgfr.jpg
http://freespace.virgin.net/bob.carter/images/centbrgrr.jpg
- you need to have access to some engineering resources........
cheers
Bob
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ChrisGamlin
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| posted on 18/1/06 at 12:42 PM |
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quote:
Originally posted by lightspear27
It would certainly be lighter than bike engine/gearbox + prop + car gearbox (type 9 for example) + prop + diff!
A transaxle would be lighter than the config you've listed above, but I dont know of a single BEC that uses a car gearbox as well as the bike
gearbox 
Reverse is usually introduced either by having a small mechanical box in the transmission tunnel that splits the prop, in forwards mode this is
straight through linking the two props, but in reverse mode it seperates the drive and directs it round idler gears or chains to reverse the prop
rotation, so giving you 6 reverse gears (from the bike's gearbox). These boxes are much lighter and smaller than a car gearbox and would have
far fewer mechanical losses.
Alternatively as mentioned above, an electric motor plus idler / ring gear can be used to provide electrical reversing as required.
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Bob C
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| posted on 18/1/06 at 12:55 PM |
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I think if you were going to use a transaxle to give reverse, you'd probably want to remove 1st 2nd and 3rd gears/synchro etc, as even when
using straight through 4th only - all these gears are turning/ meshing/ stirring oil and rotating on the mainshaft. I believe you lose a few (5ish?)
percent power in the gearbox - which would be expensive to get back!
cheers
Bob
PS keep 5th as an overdrive...????
[Edited on 18/1/06 by Bob C]
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lightspear27
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| posted on 18/1/06 at 01:56 PM |
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I think the first Pell Genesis had a fwd car gearbox/diff with the Yamaha bike engine.
Weight of transaxle car gearbox compared with weight of reverse box + car diff?
Same comparison for the losses?
Weight, reliability and efficiency of an electric reverse?
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lightspear27
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| posted on 18/1/06 at 02:09 PM |
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ChrisGamlin ...
The car gearbox solution was simply talked about in the topic in the link "modded gearbox" posted by CaLviNx.
I do not think it is the best solution. But given the price of a proper reverse box for bike engines and their reliability (or lack of it) ... a
transaxle gearbox instead of reverse gearbox + diff or car gearbox + diff could be interesting (price, weight, reliability ... overdrive possibility,
...)
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andygtt
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| posted on 18/1/06 at 06:40 PM |
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I would definatelly live with a 20kgs weight penalty for a reliable reverse and an overdrive for motorway speeds.
Andy
please redefine your limits.
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ChrisGamlin
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| posted on 18/1/06 at 07:06 PM |
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Lightspear, sorry about that I didnt follow all the links. 
I think you may be right about Pell, didnt they use a mini/metro based gearbox or something like that. ISTR it was chain driven though with most of
the innards taken out and wasnt inline with te engine like a type 9 would have to be?
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Minicooper
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| posted on 18/1/06 at 07:36 PM |
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The Pell used a Rover213 gearbox(aka Honda, this works the opposite way to other fwd gearboxes) the engine was attched to the Rover box with a 4x4
Sierra morse chain in a custom housing
I have attached an old piccie I found
Cheers
David
 
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Minicooper
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| posted on 18/1/06 at 07:53 PM |
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Found a ZX10 mini connected to a suzuki normal inline gearbox then back to a rear diff
No. 1
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Minicooper
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| posted on 18/1/06 at 07:54 PM |
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No. 2
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Minicooper
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| posted on 18/1/06 at 07:54 PM |
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No. 3
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ChrisGamlin
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| posted on 18/1/06 at 08:38 PM |
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Ah I was on the right lines, I knew it was BL / Rover 
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jamestziros
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| posted on 22/1/06 at 05:41 PM |
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Thanks
Guys
Thanks for your discussions, I'm in & out of the country so don't get on here too often, please dont think I was ignoring you all
since posting this thread.
Interesting reading.
I think I will go with an electric reverse since it will be the lightest & most favorable option since I do not plan to be going backwards too
often....!
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G.Man
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| posted on 24/1/06 at 06:30 PM |
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The biggest advantage of a BEC is power to weight...
Go with the quaiffe box and keep that weight down
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
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Hellfire
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| posted on 24/1/06 at 07:09 PM |
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Bin the Quaiffe and further improve your power to weight ratio
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G.Man
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| posted on 24/1/06 at 08:19 PM |
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quote:
Originally posted by Hellfire
Bin the Quaiffe and further improve your power to weight ratio
fair point, but you look such a knob reversing without a box..
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
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ChrisGamlin
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| posted on 24/1/06 at 09:44 PM |
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Not if you get the missus to get out and push
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Lightning
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| posted on 25/1/06 at 08:36 PM |
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Often i employ the full lock, lots of revs and drop the clutch method, as long as there is a little room.
Just a thought, maybe this is why my rear tyres are almost bauld???
[Edited on 25/1/06 by Lightning]
Steve
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G.Man
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| posted on 29/1/06 at 03:42 PM |
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quote:
Originally posted by ChrisGamlin
Not if you get the missus to get out and push
Yeah but most wives weigh more than quaiffe reverse box, I know mine does..
LOL
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
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