BEC powered Phoenix, reversing mechanism?

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reb
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Name: Alexander Grossmann

BEC powered Phoenix, reversing mechanism?

Postby reb » Sun Jul 23, 2017 1:09 pm

Hi,

where did you fit the reversing mechanism on a bike engined Phoenix?

Did anyone of you managed to fit a sprocket and starter at the back of the differential tunnel?

If I fit a sprocket on the inlet flange of the differential there is barely any place for the starter.

The only solution would be to position the starter in a way that half of it would be under the floor of the car.

However the starter would get damaged quickly in such a position on uneven road surfaces.

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pigeondave
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Re: BEC powered Phoenix, reversing mechanism?

Postby pigeondave » Mon Jul 24, 2017 11:27 pm

Im not to sure how its done as all the BEC's i know dont have a reverse.
you could try looking on the RGB forum as they have to have a reverse for racing.

http://www.rgb-racing.org.uk/rgbbb/

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adithorp
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Re: BEC powered Phoenix, reversing mechanism?

Postby adithorp » Tue Jul 25, 2017 10:32 am

I do seem to remember seeing a picture of a reverse motor 1/2 protruding under the floor of a car. Didn't look a great solution unless it was just to get through IVA and then remove... before fate removed it anyway. Where do RAW fit them?

Is there any room to fit it at the gearbox end of the prop'? I've also heard of people fitting them on one of the diff output flanges (bolt on shafts) but it seemed to me you then loose the gearing advantage of the diff, so the motor would probably struggle... All the ones I've seen struggle anyway in practice; Rather than "electric reverse" they should be regarded as "comedy reverse" IMO.

Luckily my Fury went through SVA when they weren't required and I've managed the last 8 years quite happily without.

reb
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Re: BEC powered Phoenix, reversing mechanism?

Postby reb » Tue Jul 25, 2017 5:18 pm

As far as I know a Fury has a slightly wider chassis compared to a Phoenix.

Hence I assume it will be easier to fit a starter in the back of the transmission tunnel of a Fury.

Many other seven kit cars have enough place to fit a starter in that position.

But it seems that the transmission tunnel of the Phoenix is just too narrow in the back.

I asked RAW and they told me that the starter would have to protrude into the passenger seat space (but they fit reverse boxes usually).

This was also a solution I was thinking about but then the passenger seat has to be moved forward quiete a bit.

The backrest would not rest on the panel behind it anymore.

As I have thin carbon seats this might not be ideal and might result in a safety concern.

I also thought about fitting the sprocket to one output shaft but as you noted I would loose the gearing advantage if I fit the same size sprocket.

Hence the sprocket must be much larger compared to one which is fitted on the input shaft.

Everyone who has experience with bike engined kit cars advised me not to fit the sprocket on the transmission side as this might damage the transmission.


Here the usual position where the starter is fitted, but as I explained that area is much narrower on a Phoenix.

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adithorp
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Re: BEC powered Phoenix, reversing mechanism?

Postby adithorp » Wed Jul 26, 2017 9:10 am

I assume from those photos and your having to be stuck out underneath that the phoenix diff sits lower than that. Could you mount the motor above the diff with a box on top of the tunnel or is that where the tunnel rails are too tight?

How does having it at the front damage the transmission? Its the gearbox output bearing not able to take the loading I guess.

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pigeondave
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Re: BEC powered Phoenix, reversing mechanism?

Postby pigeondave » Wed Jul 26, 2017 1:29 pm

If youre going down the reverse box route. Pick carefully. I think Fury sports cars had issues with a particular make.
Might be worth giving Steve a call (if you go that way)

reb
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Re: BEC powered Phoenix, reversing mechanism?

Postby reb » Thu Jul 27, 2017 9:03 am

I can't mount the starter above the sprocket because the handbrake lines are located there.

I am not exactly sure how the transmission can be damaged if mounting the sprocket on the transmission side.

But there are issues with space anyway as the sprocket will hit the transmission casing.

Furthermore I trust the expert I spoke about regarding mounting the sprocket on the engine side.

I am just not willing to risk it.

Despite all this I already saw someone who managed to fit the sprocket on the transmission side.


@pigeondave:

I heard that all reverse boxes are rubbish and hence my intention is to fit an electric reverse.

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adithorp
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Re: BEC powered Phoenix, reversing mechanism?

Postby adithorp » Thu Jul 27, 2017 9:26 am

Wasn't questioning the advice about transmission end, just curious about the reason.
All reverse boxes I've heard of are either noisey, blow oil out, have short lifespan or any combo of the 3.
But then any electric reverse I've seen has either
...instantly stalled the engine due to the current draw,
...needed the engine reving it's nuts off,
...had a huge car battery,
...been ineffective (especially up hill),
...any combo of the above.
I'll stick with my Isaac Newton reverse. It's only intermittently effective but so are the others and it's lighter.

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pigeondave
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Re: BEC powered Phoenix, reversing mechanism?

Postby pigeondave » Thu Jul 27, 2017 3:09 pm

@Adithorp but reb might need a reverse for IVA so Isaac Newton reverse might not cut it.

@reb go the whole hog http://eliteracingtransmissions.com/cat ... /mx200-il/

Jek
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Re: BEC powered Phoenix, reversing mechanism?

Postby Jek » Tue Aug 29, 2017 9:46 pm

I've been having similar issues on my Fury build. Reverse is temporary for IVA only. I briefly considered mounting it underneath the diff flange, but this left about 50mm of motor sticking out beneath the chassis rails....I decided this could fall foul of the IVA rules, so I ended up squeezing it in above the diff.

In order to do so I had to relocate the handbrake cables to the bottom of the tunnel. Even then, there is very little space. About 3mm clearance between the motor casing and the fuel lines.

The second problem was that there's not really anything solid at the top of the tunnel to mount the motor to. I decided the upper rails of the transmission tunnel weren't stiff enough, especially when weakened by the rivnuts for the cover panel - so I ended up constructing a frame within the tunnel which braces off the old handbrake cable mountings and a couple of other places. A real faff for something that only needs to work once! Oh and the motor sticks out above the top panel, so I had to make another one of those with a bulge in it!

I can post some photos of mine if it helps, although I'm not sure how similar the Fury and Phoenix chassis are in this area.


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