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PostPosted: Mon Feb 01, 2010 1:16 am
by peter
Hi Guys ...For those who are interested in how I'm progressing with the 6.5 honda clones, I'll bring you up to date....I've got the long bolts installed and the motor mounts on the nacelles, with new 3/4 '' bushings on the backplates where they were on the old rotaxes ....I've installed new throttle cables and new 1/8 fuel lines from about 10'' above the tank to about 12'' from the thinking on the 1/8 line was to make for less weight of gas for the pulse pump to lift....I know it lifts about 4' with a 1/4'' line but it won't keep running at full power at a 5' lift.
Just for hellry I put the 140$ motor with no govenor and just a strait pipe, back on the test stand, and with the 34x12 prop the rpm came up to 4250....this is 70lbs or so thrust off this strait engine, compared to the 77 lbs that the N R race ready yellow clone does at 4450 and for 300$ more ..... you know I think you could bolt 2 of those suckers on almost right out of the box, fill the gas tanks and go flying...... the 3.6 liter tank runs for 1 hr and 25min at full throttle....The problem I think would be the additional frontal drag....muffler, airbox, and gas tank, plus the additional weight....maybe 3 or 4 lbs...or perhaps it wouldn't matter all that much....the main reason for all this was to see if these motors could be a real inexpensive alternitive to the 185's.....hey 150.00 for a motor and less than 200$ for the prop and hub?
I'm still waiting for the other motor to come from NR Racing but I'm pretty well ready for it ....a few hours to hook up the cables and switches and fuel, and finish rearranging the panel, and see where the CofG is and take the wheel pants off and put the skis on ....well maybe a few days....we got enough snow now, but it's been way too cold.
Cheers .......Pete
Hey Wayne....I'm enjoying your new plane assembly project!!

PostPosted: Mon Feb 01, 2010 12:04 pm
by JPXman

i think the 185's don't have a thrust bearing and they work fine on lazairs, so i imagine your honda clones don't have a thrust bearing on the crank?

the fact that you're only asking what the engine is rated for is a good thing, and might even add to the argument for the "untuned" and inexpensive version.

food for thought.

now, put a redrive on that honda and you eliminate any bearing issues and can swing a really big prop..........but i am getting ahead of YOURSELF :) hahaha


PostPosted: Mon Feb 01, 2010 1:57 pm
by peter
Hi Tyler....The bearings were a major concern when I started this, and in fact I was originally going to go the re drive route on account of the fact that I didn't think the bearings were up to the thrust....In searching around for info about these clones, I stumbled on a website....Eggmotor... from England, about a couple of guys trying to get their ppc's airbourn with beefed up clones....this encouraged me to try the direct drive route...All the reading on the various Karting sites and on the eggmotor yahoo site where these guys are discussing their results with the 12 or 16HP beefed up motors, no one has ever had any bearing failure problems ....this is good news, because I thought this would be the weak spot, in fact I had already bought thrust bearings to mount externally on the shaft, and bolted back to the front plate on the engine....would have worked too, I think....I've run the test motor wide open now for over 15 hrs, first with the 31x12 prop at 4850 rpm, and now with the 34x12 at 4250....I'm using 10w30 mobile 1 synthetic oil.
I'm thinking Tyler that takeoff power at 4500 rpm is not going to bust these engines, and I am quite sure they have enough guts to turn a 34x14 prop at more than 4000, and give the same amount of thrust....these motors unlike the 2 strokes perform better at lower rpm's.....peak torque at 2500 rpm.
My thoughts for now ......Cheers.....................Pete

PostPosted: Mon Feb 01, 2010 9:02 pm
by JPXman
well i hazard to say you've thought through all critical details - time to become a lazair test pilot. are you running the fuel lines the same way a 185 lazair is setup? with the tank vented and two individual lines going right from submerged gas to each carb? i remember you mentioned fuel pump - try to keep each engines' fuel supply separate from the other. if you're going to use a pump, use two pumps.


PostPosted: Mon Feb 01, 2010 11:23 pm
by peter
Hi Tyler......The fuel system uses the same setup as the rotax...I've replaced the old original lines with tygon including the brass check valve filters, from the tank to the motors ....From there the fuel is picked up on each engine by an external mikuni fuel pump that receives its pulse from a 1/4" line off the intake other words, each motor has its own fuel system......I'm counting on this fuel delivery system being able to lift the gas from the bottom of the tank, and suck the tank dry at full throttle.....If the pumps can't do this I'll either have to go to a tillotson carb and manifold adapter, which is pretty expensive, or mount a 2 gal or so teardrop tank on the nacelles, which would be cool, or just simply put the original tank back on, which of course would be the most practical....That little 3.6 liter tank will run the motor full throttle for almost 1 and 1/2 hrs....that's long enough for me or my bladder....but I'd prefer being able to use the 5 gal tank.
I'll get some pictures on how I've moved the switches and tiny tacks to the panel on the pod and also some of the motor installation and throttle and choke setups.....everything so far is really pretty strait forward...
Thanks for your interest and concern......I appreciate it....................Pete

PostPosted: Tue Feb 02, 2010 3:58 am
by ozzie
I had thought of these types of engines a while back but never followed throgh with trying one so i'm interested to see how you go with them. One thing that i have pondered on is the oil system and how that works. will it be able to cope with a high angle of attack for a period of time?

PostPosted: Wed Feb 03, 2010 1:17 am
by peter
Hi Ozzie...I think we have all thought, at one time or another, if there might be an alternative engine that wouldn't cost an arm and a leg, and I am pretty sure this is going to do the trick.....These engines have a dipper on the bottom of the rod that just clears the bottom of the crankcase so as long as it can reach the oil there is going to be lubrication....I'd guess at least a 45 degree angle would be the max sustained climb, and that would probably hold true too for the gas in the float bowl of the carb.....I don't think there will be any problems in that regard because we are such a sedate bunch of guys ha ha....45 degree climb
Shannon.....I searched the web, time after time looking for a site that would give me some idea of the size of prop for small HP engines, and the one I finally stumbled on is for large R C model planes and it is exellent.....Just google.... static thrust calculator...and that's it.....I think it is reasonably accurate, judging by how the rotax's would turn the 31'' for speed and hp required and comparing those figures to the honda and what it could do with the same prop.
Got my other motor today, so I'll get it running on the test stand and see how it the exhaust header modified and the mufflers and supports installed so I"m progressing.
Wish I could send a bit of our cold weather down your way Ozzie to cool you off a bit.............Cheers...Pete

PostPosted: Wed Feb 03, 2010 2:39 am
by ozzie
It is great to see the development that you are putting into this engine. Maybe the opotunity for you to make up some kits to retro the old two strokes. fingers crossed.
Just a little bit of cold will do. rain has been a well recieved here in Sydney over the last month with a bit more to come. With the humidity it feels a bit like living up north in the tropics. At least no bushfires this year.

PostPosted: Thu Feb 04, 2010 9:26 pm
by Shannon
Pete do you have a part number on your prop Hub ?

PostPosted: Fri Feb 05, 2010 1:23 am
by peter
Hi Shannon....the hub is the steel one...QM1011S.....28$ and change....Just barely big enough for the 34x12's, but after 5 hrs seems to be hoding up ok
Cheers .....Pete