Hello everybody,

First, let me briefly introduce myself.
My name is Cyril Wichers, I'm from the Netherlands and my hobby is RC tractorpulling.
During the last 15 years or so, I've built several pullers, powered by ic engines, ranging from single .21 buggy engines to twin .91 ducted fan engines. I also did some experimental stuff, like converting a nitro engine to run on diesel, converting a 2.5 Cu/In 2-cilinder weedeater engine to run on methanol and joining two OS .30 Wankel engines, to form a single unit.

Now I'm planning a new project, involving big gas engines.
What I would like to do is build a puller powered by the biggest and most powerful gas engine I can possibly fit in it.
In the end, it should look something like this:


I'm limited to a max weight of 5.5Kg for the complete puller, so the max weight for the engine (including ignition and exhaust) would be about 3Kg (96.5 ounces)
Maximum width is 320mm (12.5 In) Maximum lenght is 426mm (16.7 In) measured from the centre of the rear axle to the front of the puller. This allready implies that using tuned pipes is not an option. I'm even considering running open exhausts (or just headers) to save weight.

I'm thinking of using one of these three engines: BME 115, 3W 106, DA 100 (these also fit in my engine-budget, I'm thinking of spending around 1000-1200 Euro's (1350 - 1600 Dollars)
The question is, which engine do you think will fit my needs best? Maybe there other alternatives that Im not aware of?

Thanks in advance,
Cyril

MVVS 116

Weight: 3220 grams including ignition and battery
Engine width over the plugs is 330mm

Too heavvy and too wide, nice engine though!
Come on guys! There must be more of you with an opinion on this!

Very cool hobby.If you can just post a video or email me one i'd just love to see that baby run.Tractor pulling is a big sport with me but i,m sorry i don't have any knowledge of the particular need you have. [email protected]

See if you can find a Quadra 100 single. It has a reed valve intake and a rear exhaust. It would be used so might be easier on the pocket book.

Does it HAVE to be a gas engine??

How about a http://www.wrenturbines.co.uk/product.php?pid=3

Just a thought - very light and powerful but maybe a bit pricey?

Thanks for the compliment! You can find a couple of (older) videos here: http://home.hetnet.nl/~cyril-wichers/video.htm Just click on the pictures.

@tkg: I searched for the Quadra (didn't even know they made them anymore) It looks like a powerfull engine, so that's good, but I don't think I would like to use a single cilinder. It would just be too big (high) in comparison to the rest of the puller. Thanks for the input anyway!

@Skipper Billy: Too late, there's a guy in our club who's been buiding them and using them on his pullers for several years:

Oh well, I'm more of a piston-type of guy anyway[sm=wink_smile.gif]

Since you want a twin, a BME 102 if you can find one.

Why a 102 and not a 115?

The newest 116 is 327mm over the widest dimension of the standard plug caps. Still too wide I suppose?
What if you can slice off 10 mm each side from the caps by eliminating the caps and make a direct plug connection without the caps? You get rid of 20mm that way.
Powerwise, the MVVS cannot be beat in it,s class

Hello Pe,

I must say that the 116 is very tempting. The power is good, the looks are good (I like the carburettor on the back of the engine, instead of it towering above the crankase), if what you say about the plug caps can be done, the dimensions are also OK. It's just the weight that I'm worried about. Do you think it would be possible to put the engine on a bit of a diet, without damaging it's structural integrity?

Slightly off topic:
For our US readers, in post #7 follow the anaconda movie link. Apart from mini tactor pulling, Wooden shoes are still worn in the Netherlands. I used to wear them as a kid, until callusses on my upper feet became prohibitive. Nowadays they have leather strapped upper parts, which are much better.

@ Ceryl,
Great website!

I would run the biggest single on a tuned pipe on all the nitro I could shove into it and probably have it running well into the teens rpm wise
Any of Those twins would fly apart treated like that . plus NONE of em can breath as much as one can get with a huge single - -simply can't get the flow thru the passages .
Design wise they simply are not ready for that kind of abuse
Look at old Kart engines - I use Mac 10s years back - these can really take a beating.
Now -If'n yall like tractor pulls -and you have a Satellite /cable TV- tune into station RFD -and watch the pulls and old time tractors n saw mills n simply great entertainment for thos who love machinery
I watched a guy blow up a Minn.Moline - the low end came apart - some of th e pulls are Unlimited class -stunning power.
(Somehow I just KNEW that Pe secretly wore klompfers Ja!)

Dick,
Apart from the "klompen" that I used to wear as a kid, it is very important to look at the fact that the engines have no time to run hot in this contest. You could run them previously with sufficient oil, and during the contest with no oil at all for all out power, and get away with it. Drag racers seem to do it all the time. In some of the videos, you see a lot of oil smoke, even though I know that my customer (poppeye) runs at only 10% oil. The engines would barely survive this in normal flight practice, yet they have no problems or even the slightest carbon from this kind of " abuse " . After a season, the engines look like new! An eye opener for sure, which makes me remind a supertigre that I prepared for UC flight with a soft iron Dykes ring. The engine laster forever until I decided to use it for RC. 5 tankfuls did the trick in relaxing and wearing down that ring to usefulness. It just goes to show how different operating conditions can lead to different design requirements, especially if the engine never sees more than about five seconds of all-out power!

Racing all out is a different ball game - for certian!
the drag racers here started -- years back -- filling the water passages with metal - running solid blocks - -
also running LOTS of fuel helps control temps . waaaay back the local hot shoe -ran Ford flathead blocks with ARDUN heads which routed the gasses out of the block and got a few runs at a time before th wimpy Ford 3 main block blew up. this was -- 50 years ago - I was running a modified Ford Flathead and could not make anywhre near that power as it simply could not breath like the hemi ohv setup.
I fixed that - went to a FI head 283 Chev-setup

For your application, the engine diet could mean removing most of the cooling fins, and other metal stuff that is not needed for the very short power burst that is asked for (form follows function) . A weight loss of 20%, if cleverly approached maybe? The approach is much like drag racing. Get the engine up to temperature, ask for a power burst, and before the engine gets into the distress zone, shut it down. The total engine mass that can absorb and conduct heat is of very little importance here. Even if cylinder temperatures reach 200C at the end of a run, the oil inside still needs time to evaporate, which time is not available, so your engine will not be subjected to marginal lubrication. The crankcase will stay quite cool because time to conduct cylinder heat also is not available, so the main bearings will need little lubrication. The reed induction will help tractability quite a lot.
The spark plug caps, if removed may provide extra radio interference, but since you never are far away with your transmitter that wil hopefully not play a large role in RC control over your puller.