I don't always do the brightest things, but looking hard at this little beast for a class II carrier build. It's one of there ducted fan engine's. 


Thinking for a Mauler or Guardian.  Not sure if these can really throttle down very well though.

That looks like a real brute power engine.

The only way to find out about the idle is bench running.

You might need an exhaust restrictor valve or a muffler or a pipe.

Looks like the specs are somewhere betweeen 2.7 to 3 ish bhp up around 20-22,000 rpm on the ducted fan.  I was looking around trying to find any discussions on guys using these DF engine's with normal props  and found some suggestions of 10X8 & 10x10 props on some RC stuff.... around 20 oz.... 

I have not used the 65 version but i do have a 40 and 46 version and they are strong engines. I would suggest some sort of pressure like crankcase(which will take some work to get working right) or exhaust/muffler pressure(way easier). It doesn't have to be complicated some sort of slip on tube that will build some back pressure with a fitting on it.

I would just try it first on a bench to see what it runs like. The other potential issue is that it is probable set up to run on a pipe so it might not be very happy with open exhaust. The DF engines that I have have been retimed (not by me) to run open exhaust and high nitro. They are not very happy with anything less than 50% usually run 65-70.

I doubt that you will see 20000 rpm with it but would probably run ok on a 10-8 or 10-7. I think that the 10-10 would be too much for it.

Yeah I am realizing I will have some choices to make.  TJ mentioned choosing between piped and low nitro versus open and lots of nitro,which it sounds like you are in the open and high nitro camp. Once the little hooligan arrives I may pake a post in the engine set up section once i try and digest the rules and come up with a plan lol. Plus I get the blade tip speed  thing as well so will keep that in mind.

How do you like your 40/46 versions?  How long a life do you see and what problems if any doyou need to keep an eye out for using them for carrier?

In the late 90's, I set one up for Dale Gleason for "modern" Class II. His was the earlier disc valve intake instead of the drum valve intake. This allowed us to assemble it "wrong" so it would run backwards. It was set up for suction with some version of 61 front intake carb.(stock timing) On 50% nitro and an APC 10x6 pusher prop, high speed was usually in the 17sec. range. It was not as fast with the 10x7 or 10x8 APC's.

In looking at the old Peter Chin evaluation from a magazine in the 80's they show the exh duration of 165 degrees, I can paste the article file if that will help.  I'm not sure where that falls in the open versus pipe or tuned pipe range.

That motor is very strong and very heavy. One of our guys used one successfully 'back in the day'.  Glo plugs were cheap then so  70-10-20 was the bomb. The speed guys around here liked them too.  I would definitely recommend an exhaust valve. We used to use the K&B marine valve.  Crankcase pressure is best with a carb but can be tricky to set up.  10x8 - 11x8 wood prop.  TS
  If you get it rocking it may want to pull you off your feet.  In the olden days (70's-80's) we would regularly run  15-16 sec  TS

As reported in the NCS HLL newsletter, Terry Heron recently did a high speed of 14.86 (121 MPH) with what I assume to his father's OPS powered Judy. Maybe he built a new one.  I don't know.  Either way, it's a lot of speed for a scale model plane.
Hide behind a van.

Same engine, third version airplane. It was indeed awesome.

Well it showed up and it looks NOS it's never had fuel in it    I, ah am kinda thinking of jumping off the real deep end and seeing if I can fit this with its RV in to a Mottin Skyraider.  That would be insanely cool. 

I know I found some thoughts from Paul on th Mottin Skyraider as he built a really nice one....  You really think it is too reasonably small for a .60 or in this case a .65RV?

I'm honestly not sure one could find the room for that RV in the Mottin Skyraider anyway...... But man it would be insanely cool...

Dennis, Years ago I built 2 Skyraiders. One was the .40 size and one was enlarged for a McCoy .60 and ended up with a Fox Eagle .60. That was a good combo and placed at the 73 Nats in the junior class.  As far as available designs, maybe the Mauler.  Pretty sure my pal had the os in a Guardian. It is a big ass motor!   TS

Yeah it is big for a little plane for sure! I have the article printed for the little Mottin skyraider at 30" span and have a set of plans on the way. If I can't figure out how to make it work in the Mottin Skyraider, probably just go with the Guardian as the top stand by.

Hoping Paul Smith will stop by and repost some of his pictures of his Mottin plane as well!

I built two Mottin Skyraiders.
One with an Enya 60RC and one with an OS Max FX 25.

The successful prototype by the designer used an ST 40.  I came to believe that idea of a 60 was a bad dream.  I followed that dream and did not last long.
But my 25-powered model has lasted almost 20 years.
If I was to build a model for your engine I would get all the wing area I could get within the 44" wingspan.

The middle pitcher is a Hobo Sandy that I pho-grapped at NKP.  The Hobos would arm-up their 12 weapons next to us before takeoff.  This is then root cause of mem favoring the design.

Package two.  Pack one was full.

This plane was a clear dope and dyed silk for about 15 years.
Now it's gray Klass Kote.

Package three.

I made it so I could cut into it to fix the tank and bellcrank. But thus far I have never needed to.
I only took off the cowling once, when I repainted the model.

This plane will not beat a full race 40, but it got a lot of prizes when the full race 40's crapped out on low speed.

Thanks Paul!  I got soome digesting to do...
Question, why does no one turn the engine head down in carrier? I was reading one of the benifits of the m01 was that it had a high wing so the rotation point was higher and helped it hang better.  I would think turning the engine head down on a mid or low wing would create the same effect (to a lessor degree) and help it out some if it were a hanger?  Any thoughts on that theory?

If the main reason was to keep from bouncing the head, I could understand that but was wondering if there was some other reasoning.  I guess it would drive taller landing gear... Maybe chance catching a wire on the glow plug?

I like side mounted whenever possible.  That way, either upside down or upside right, the engine never hits the ground, deck, or pavement.

In addition, with side mounting, the engine adds to the tip weight.

Finally, inverted mounting can cause a hydraulic lock when starting and upright allows the engine to flood via overflow from the spray bar.  Side mounting cures both of these issues.

I have an OS 65RSR in a Sterling Guardian. It is set up like I described for the 65VRDF: reverse rotation and suction, APC 10x6 pusher. (The remote needle shown was ultimately eliminated) It goes about 110 mph on 10%.

Quote from: Paul Smith on June 26, 2024, 08:33:44 AM
I like side mounted whenever possible.  That way, either upside down or upside right, the engine never hits the ground, deck, or pavement.

In addition, with side mounting, the engine adds to the tip weight.

Finally, inverted mounting can cause a hydraulic lock when starting and upright allows the engine to flood via overflow from the spray bar.  Side mounting cures both of these issues.

I wondered if to the side would help tip weight when I started thinking about it.
The other problems for up and down make sense.

Even turing it sideways would still help some with center of mass and not putting a big bobweight three inches above the wing, not that it matters a great deal...  More just thinking or over thinking stuff.

Bill, am I right in thinking since my enigne is the later version I can'e set it up for reverse rotation?  What performance benefit would I be losing runing it normal rotation?  Sorry a rookie question.

Quote from: bill bischoff on June 26, 2024, 09:42:34 AM
I have an OS 65RSR in a Sterling Guardian. It is set up like I described for the 65VRDF: reverse rotation and suction, APC 10x6 pusher. (The remote needle shown was ultimately eliminated) It goes about 110 mph on 10%.

Man that .65 sure fits nicely in that Guardian!    Much better than I can envision it fitting in the tiny Mottin Skyraider lol.  I just keep going back and forth.... I suppose the answer is build more than one plane   

If you are going to fly Nostalgia Carrier, and not try to prop hang, the reverse rotation isn't nearly as important. However, if you can find the disc valve parts, they are a bolt in replacement. "Back in the day" when ducted fans were the only choice for flying jet models, I was able to trade "new style" parts to a ducted fan guy for his "old style" parts. You may also find a CL speed guy with some old parts. It is probably also possible to make a new notch for the crankpin in your engine's drum rotor to reverse the intake direction. If you don't fully understand what this means, you should find someone who does to help you.

If you are going to go for "modern" slow flight, the torque from a reverse rotation engine will be a significant asset in keeping the plane out at the end of the lines during slow flight, or any time you "goose" the throttle.

Whatever route you choose, heavy, loud, fast class II models are a rush to fly!

Love this stuff!   BTW  I have Guardian kit sitting around.

Quote from: bill bischoff on June 26, 2024, 07:13:26 PM
If you are going to fly Nostalgia Carrier, and not try to prop hang, the reverse rotation isn't nearly as important. However, if you can find the disc valve parts, they are a bolt in replacement. "Back in the day" when ducted fans were the only choice for flying jet models, I was able to trade "new style" parts to a ducted fan guy for his "old style" parts. You may also find a CL speed guy with some old parts. It is probably also possible to make a new notch for the crankpin in your engine's drum rotor to reverse the intake direction. If you don't fully understand what this means, you should find someone who does to help you.

If you are going to go for "modern" slow flight, the torque from a reverse rotation engine will be a significant asset in keeping the plane out at the end of the lines during slow flight, or any time you "goose" the throttle.

Whatever route you choose, heavy, loud, fast class II models are a rush to fly!

Thanks Bill, My general interest is probably more in the nostalgia so not really planning on hanging it.

As far as the reverse rotation, I'm assuming for the disc one your just flipping the disc over like flipping a plate so the drive pin hole is on the other side of the opening for reverse rotation.  Think my ST .65 is like that although that enigne is pretty beat up maybe just a core, never really looked at it too deeply.
Also assuming on the drum you can't physically just flip it over in the same way so in order to get the same effect of moving the drive pin point you would need to add the notch you mentioned.  I'll pull the back cover off and see what that drum looks like and see how feasable that looks.  If I went that way, I might be able to set up a jig on my lathe toolpost so I could clock it correctly. BTW, the box on this one is stamped 1989, so I assume it is definitely the later drum style?...