stunthanger.com
Engine basics => Engine set up tips => Topic started by: Paul Allen on May 31, 2023, 07:56:12 PM
-
Hi, is anyone running this setup,I built a Miss BJ profile and powered it with the OS Max S35 with ABC piston and liner
just cannot get it to run how I want,I have used Brian's P/L before in an OS Max FP 40 and ST46 with good results but the Max 35 just is not working, have played with head shims and venturi size , a number of props. Maybe, it just does not like side mounting.
Model weight 38 ozs.
Just interested if anyone else is running one side mounted.
Thanks
-
Run a Std. OS 35 in the Phantom , side mounted . A 10 x 4 three blade Tornado had it like a tractor on 70's L Wt. in calm air , Sounded like a Maserati though .
Intake size and muffler type said to be relevant . Sound more like a Good FP on that prop , V Diferant 4-2 run . Id think two hours running and it'll of ' Consistantised ' itself .
Low Time its still working itself out . The Olde ' Once it stops increaseing run time ' per tank , its runnin . Fine . Mines Std & Std Intake & 703 muffler . Wotcher cut the long bolt
alf fru , so it DOSNT TEAR THE LUG OF THE MUFFLER if the earth tilts as you pull out , a GUST comes across and pulls it into the drain or a tree walk out in front of it .
-
A SIDE MOUNTED OS 35 S , sans Gardner P / L . : wore out one in oneof these . Liners aint ardened . They used to polish & fit and heat treat ( 3 x 1 Hr @ 300 Deg. And the PISTON . ) & lap the lot. in the US in parts .
(https://stunthanger.com/smf/index.php?action=dlattach;topic=41658.0;attach=250091;image)
the 9 x 6 is useless . the 10 x 4 HARD is the one , or a 11 x 4 thinned and tooned Wood . Pull the L E up or down , sanding block , to fine tune speed . Like I said , Sounds like a Gnarley crackly FP 40 . Almost .
Its Own Unique Sound Even .
Give it time , olde Bean .
-
I would only have two options for you. One would be to make sure the cylinder liner is in correctly and not backwards. The other is that you may not quite have things run in. I have a Gardner P&L set in a LA.46 and did a test stand break in as per instructions after a trouble free assembly. I put the engine in a rather heavy airplane that I has a stock LA.46 in before it, and was running a APC 12.25-3.75 in order to pull the weight, and the stocker ran well in it. After installing the Gardner set in another engine, I pretty much had what you describe, it just would not pull that big prop like the stock engine would. It didn't run "bad", it just didn't seem like had the same power I worked with it for the rest of the season, then hung it up on the wall for the winter. The following spring we headed back out to the field, and with enough time passing that I didn't remember exactly where I was or what I had, so I just started from scratch and put up a flight with the same fuel and everything else I was using, and it was like a different engine!! I was running some 11 inch props through all that previous testing, and that gave the engine the rest of the break in it needed. I consulted Brian about it and he agreed. Some sets come out just that little bit extra tight that they need the running in. Put the engine on a test stand with a 9-4 prop for about a dozen more runs or finish the run in in a fun fly model running smaller prop than you would normal for a dozen flights of so, and then see what you have. Put everything else back to "normal" configurations during this. Try this and see what results you come up with.
Type at you later,
Dan McEntee
-
Paul, Perhaps list the symptoms so I can give suggestions.
-
Brian
The motor seems to be running hot,and has a fair amount of carbon on the piston.
Running 11% Klotz,11% castor, 5% nitro, I had a similar issue with the ST 46 P/L at the start
it was over compressed with the standard head ,adding shims solved that. I have tried this with the
Max 35s but still not resolved, only using 3 oz of fuel for 7 minute flight, venturi is 0.281" ST needle valve,
was using Thunderbolt Hot plug, even tried a Medium heat plug.
Running fast 4 on ground, speeds up to wet 2 after a lap not what I want, have tried many props,
thought it was a tank problem, as soon as it went inverted it dropped back to 4 cycle.
Adjust height of tank,still no good, than it will go rich up right at different times in the pattern?
Fuel is not foaming, no vibration down lines, tried different prop dia, thinking over or under propped.
The reason for asking about side mount,I have an Enya 40 XZS that would not run right side mounted
yet mounted upright or inverted its runs great.
-
Brian
The motor seems to be running hot,and has a fair amount of carbon on the piston.
Running 11% Klotz,11% castor, 5% nitro, I had a similar issue with the ST 46 P/L at the start
it was over compressed with the standard head ,adding shims solved that. I have tried this with the
Max 35s but still not resolved, only using 3 oz of fuel for 7 minute flight, venturi is 0.281" ST needle valve,
was using Thunderbolt Hot plug, even tried a Medium heat plug.
Running fast 4 on ground, speeds up to wet 2 after a lap not what I want, have tried many props,
thought it was a tank problem, as soon as it went inverted it dropped back to 4 cycle.
Adjust height of tank,still no good, than it will go rich up right at different times in the pattern?
Fuel is not foaming, no vibration down lines, tried different prop dia, thinking over or under propped.
The reason for asking about side mount,I have an Enya 40 XZS that would not run right side mounted
yet mounted upright or inverted its runs great.
With the venturi and NVA you are using, I would think you would need more than 3 ounces for the pattern. And leaning out after take off is another sign of something wrong. I suspect a leak somewhere. Check the engine crank case and for cracks and back plate for leaks. Is the engine sitting nice and flat on the mounts?. If everything is right and no leaks the engine should richen up a tad once you have made a lap or so.. If you think the tank and fuel lines are OK, do you have another engine, preferably a Max-S.35, that you could try on the airplane? From your description it just sounds like it's going lean a bit once in the air.
Good luck with it,
Dan McEntee
-
The further outboard the tank is , the more it would lean out .
To be rediculous , if it were out at the end of the wing , youd notice it .
As a TEST , try ( if it will fit ) mounting the tank on the INBOARD side of the fuselage .
The Harder the planes going the more fuel it will get .
A old baffled OS 35 is going to burn a bit of juice . As In , it should need more than a modern schneule thing ,
If its not getting enough that sorta explains the cooling / running hot .
Another stuff up would be 1/16 bore plumbers copper tube tank feed pipe . It'd need a bigger bore .
The Blue Phantom , when a FSR 25s in it , the TANK is entirely INBOARD of the plug in intake mounted spray bar.
Lower you go the richer it runs.
Is your tank uniflow ? .
-
Dan
Removed Max 35S, fitted early model OS FP 35 ( steel piston version ) 5 flights all good, today.
Model flies great when you get an engine run!
Dan will strip down Max 35S and check inside and clean the carbon out.
-
The further outboard the tank is , the more it would lean out .
To be rediculous , if it were out at the end of the wing , youd notice it .
As a TEST , try ( if it will fit ) mounting the tank on the INBOARD side of the fuselage .
The Harder the planes going the more fuel it will get .
A old baffled OS 35 is going to burn a bit of juice . As In , it should need more than a modern schneule thing ,
If its not getting enough that sorta explains the cooling / running hot .
Another stuff up would be 1/16 bore plumbers copper tube tank feed pipe . It'd need a bigger bore .
The Blue Phantom , when a FSR 25s in it , the TANK is entirely INBOARD of the plug in intake mounted spray bar.
Lower you go the richer it runs.
Is your tank uniflow ? .
YES it is.
-
Dan
Removed Max 35S, fitted early model OS FP 35 ( steel piston version ) 5 flights all good, today.
Model flies great when you get an engine run!
Dan will strip down Max 35S and check inside and clean the carbon out.
I haven't done any of Brian's OS .35-S P&L sets, did it include the rod? Could it be installed backwards ?? If he does another run of those I want to get a couple.
Keep us posted,
Dan McEntee
-
Cannot remember ,but when I got the St46 P/L from Brian it had no rod,so I think the Max 35S would
have been the same, but I had an aftermarket rod, I think from SSW or Randy, rod is fitted correctly.
The motor was test run in an Oriental with T/muffer from my notes there was no issue,it was oiled and sat
in a box till I mounted it in the Miss BJ profile. Plan is to clean the carbon, reassemble and run on test stand
with no muffler at a fast 4 cycle just switching to 2 cycle,take some RPM readings and then try it with a muffler.
-
Dan
Re checked notes, I used a wrist pin from an OS FP35 with the teflon pads in the end
so did not come with a rod, this was after reading some info from Randy Smith about the brass end pads
in the max 35 S wrist pin marking the liner. Motor has been cleaned, the only thing I found was the
wrist pin was a bit tight in one of the bosses in the piston, thats about it, cleaned up, slide fit.
-
It could be a varnished bore.
-
The upright/inverted switch suggests the tank is no bueno. I would be removing it and pulling the back off, if it is a tin tank. Store bought fuel tanks can be NG from the start, especially NOS and NP (newly produced). ;) Look for brass tubes (change to copper), solder flakes, corrosion, and of course, leaks. I like to solder a flat washer at each place a tube pierces the tin, because I've had too much trouble with cracked solder joints at those points. Spreads the stress concentrations and acts like a thicker tank material. Yes, it adds weight. H^^ Steve
-
Dan, you have a pm
Luke