ETLB Squawk Forums — Archive

Are there any examples of an Airbike equipped with an industrial twin engine? And how satisfied are you with the performance?
Rgds Erkki

To the best of my knowledge, I don't think anyone has ever put one of the v-twins on any of the Mini-Max airframes. I do think they would work (depending on power output). The guys at Hummel are now selling a v-twin they claim puts out 35-40 hp. That might get the job done on a Mini-Max.

https://www.youtube.com/watch?v=odOwW7uLzQA

There was at least one in Sweden that flew with a industrial v-twin!

I'm putting a B&S 993 in a 1600R.  I'll report details here when I get it running.

ken, what is your firewall forward system going to weight?

The guy who created the legal eagle is successfully using:

https://youtu.be/MBMAdLkYtz0

Hmmm, if this works in a Legal Eagle, then it might work in a Airbike as well!

Quoted from erkki67 ken, what is your firewall forward system going to weight?

I need to check-in more often.
Briggs and Stratton 993cc Direct Drive:
Bare Engine     68.6     
Carbs-VM32 (1.6 x 2)     3.2     
Exhaust (1.3 x 2)     2.6     
Oil (2.4 qts)     5     
Ignition- 2 coils, 2 HEI, 4 pickups, 2 switches     3.5     
Prop Flange     2.8     
Remove Governor     -0.73     
Crankshaft Taper to 1-7/16” adapter     1.1     
Camshaft Weight Loss     -0.43     
          
Total Engine Weight     85.64     
                    
Stock Cam     3.07     
DynoCam     2.64     
Difference     -0.43     
Governor     -0.73     
Weight Lost     -1.16     

Note that a redrive will add ~11.5 lbs.

I need to check in more often as well.

Thank-you @Kenpowell for that information. I currently have a Hirth 2702 and plan to fly with it for a while. Since I have no love for 2-strokes I was thinking an industrial v-twin might be an "okay" engine for my 1700.

I'll try to find the video where a guy made a CHAIN PSRU. Certainly cheap and light, but not typical.

Hello Ken, do you have any new data available? rgds Erkki

I haven't touched the engine  (briggs 993cc) since summer.  I hope to get back to it and get it running sometime this summer.  I have to build the ignition system with 4 pickups, 2 HEI ignitions and 2 coils.  This allows hand-propping at 0 / TDC and running at 28 degrees BTDC.  The engine needs a separate ignition for each cylinder due to being a 90 degree 4-stroke plus separate pickups for 0 TDC and 28 degrees BTDC for each cylinder.  Sounds complicated but it really isn't.  The engine will be direst drive and will use an Eiffel prop to test for horsepower.

hello Ken, do you have any news?

I have had a partial knee replacement and a rotator cuff repair since Jan 5 but started working on the engine again today.  How's that for timing?  I turned a 2" diameter 'puck' to mount the reluctor for the HEI ignition pickups.  Not much, but it's a start (again).

What hp do you think you'll get out from this engine?

Quoted from erkki67 What hp do you think you'll get out from this engine?

40HP at 3600 RPM and 48HP at 4500 RPM.

I love those figures.

So with the redrieve and the engine you'll get about 97lbs which equals about 44kg, for a calculated 40+hp.

What are you going to rework on the engine, except removing the RPM limiter ?

I am going to chime in here, some may remember back in 2008-2009 I was flying a legal eagle with a 990cc generac conversion. It developed 38hp at 3600rpm and was turning a culver 74x44 prop via a 2 to 1 reduction drive. takeoff and climb performance was terrific, off the ground in under 50ft and climbing 1200 fpm or better, cruise speed was slow though, about 45-50 mph at 3000rpm. fuel consumption was also good at 1.25gph!

Valley engineering used a tensioner pulley on the slack side of the belt to keep the power pulses from the engine from destroying the belt prematurely, a feature i see absent on the ace redrives and most redrives today. look up World's Okayest Pilot on youtube and you'll find videos of the plane on my youtube channel.

Chris

Quoted from erkki67 I love those figures.

So with the redrieve and the engine you'll get about 97lbs which equals about 44kg, for a calculated 40+hp.

What are you going to rework on the engine, except removing the RPM limiter ?

HEI Implementation

I'm building a Briggs and Stratton 993cc generator engine for my minimax 1600. The plan is to be direct drive, no generator/alternator (to remove the 19 lb flywheel), and no starter.
For the ignition system I'm running 2 separate GM HEI's for each cylinder. This will be a reluctor type system. For each cylinder:
One HEI at zero degrees (top dead center) for hand propping and one HEI set at 28 degrees BTDC for full power. Start on the 0 degree HEI then switch to the 28 degree HEI after the engine is running.

Quoted from kenpowell
HEI Implementation

I'm building a Briggs and Stratton 993cc generator engine for my minimax 1600. The plan is to be direct drive, no generator/alternator (to remove the 19 lb flywheel), and no starter.
For the ignition system I'm running 2 separate GM HEI's for each cylinder. This will be a reluctor type system. For each cylinder:
One HEI at zero degrees (top dead center) for hand propping and one HEI set at 28 degrees BTDC for full power. Start on the 0 degree HEI then switch to the 28 degree HEI after the engine is running.

Thats a very similar setup to the  Chotia 460 on my weedhopper only with points. 1 set of points fires at TDC for starting and one at 25deg BTDC for running. after starting you just flip a switch to select the other points set. word of caution though, I was letting a friend fly the hopper and she flipped the switch the wrong way before I flipped the prop. the result was 54 stitches and 2 broken fingers.

Chris