# Ace Aviation Redrives.

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#### John Penry-Evans

##### Active Member
Professionally designed redrives for many engines since 2010. Single cylinder and V-Twin 4 strokes from 200 cc to over 1200 cc. Image is for a Briggs and Stratton 993 cc engine.

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#### Victor Bravo

##### Well-Known Member
HBA Supporter
Is there a "slack side" tensioner or spring loaded idler on these redrives similar to the system developed by Valley Engineering?

Although I am NOT an engine expert, it is my understanding that the tensioner effectively resolves certain problems that are common with belt reductions, and that the benefit is worthwhile.

#### pictsidhe

##### Well-Known Member
No seperate tensioner or idler. The prop pulley is on an adjustable eccentric for tension adjustment. TV mitigation by belt slip.

#### pictsidhe

##### Well-Known Member
What would be pitch between shafts, pulley and belt sizes for a small block vanguard with ~2.7 reduction ratio?

#### John Penry-Evans

##### Active Member
Is there a "slack side" tensioner or spring loaded idler on these redrives similar to the system developed by Valley Engineering?

Although I am NOT an engine expert, it is my understanding that the tensioner effectively resolves certain problems that are common with belt reductions, and that the benefit is worthwhile.
------- > Whilst doing as much information gathering on other redrive types, we had a few people that said that an idler can actually induce some vibration (Many people who have these idler type had told us). There is a huge gap between those pulleys that can induce belt slap.
We have reduced this measurement to a bare minimum between the pulleys. No one has complained about any vibration to us in over 10 years of producing them.
And of course our redrives have a quick and accurate eccentric shaft to tension the belt.

#### John Penry-Evans

##### Active Member
What would be pitch between shafts, pulley and belt sizes for a small block vanguard with ~2.7 reduction ratio?
-------> As I mentioned in another reply our pulley OD to OD has the bare minimum of clearance. 3 to 4 mm. This keeps the unsupported belt length shorter when it leaves the pulleys.
I would have to know what RPM you are going to run your engine at? What diameter prop are you going to put on?
Would it be possible to email me?
info@aceaviation.co.uk

#### pictsidhe

##### Well-Known Member
5000rpm, optmistically hoping for 40hp. 84" prop.

#### John Penry-Evans

##### Active Member
5000rpm, optmistically hoping for 40hp. 84" prop.
I know of a few of these engines that have been tuned to around 4800 to 5000 Rpm. They seem to be getting around 35 - 36 hp. Both of the ones that Im thinking of use 60 inch props. One has measured the thrust at approx 100 Kgs.
Your 84 inch prop is huge?
What aircraft is this going on?

#### pictsidhe

##### Well-Known Member
Huge is the correct word.
It will be going on a 2/3 scale. Hawker Hurricane Mk103.