Model Diesel Engines - Page 302 - RC Groups
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Jan 23, 2013, 02:25 PM
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You’re correct Brokenenglish, I’ll have to eat crow and will take back what I suggested. You’ve a much better suggestion than mine. I didn’t realize that the nose moment was so long.
If I were building this model “full size”, I guess I’d wait until I was just about done and then see how much nose weight I needed for the CG. My Play Boy (9ft), Lanzo Record Breaker and Lanzo Bomber (8ft) are all rather short nosed and require close to an extra 1 lb (1/2 kg) of nose weight.
Now if we were to build the 1/2A size (attachment PDF), we probably wouldn’t need any extra weight.
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Jan 28, 2013, 04:41 AM
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Why would you want to add nose weight to a bombe r or a playboy .Im on Bomber no 91 at the moment and Playboy no 68 and have never had to add weight of any sort or si ze to them .112percent playboy,Thunder Tiger 46 ,balance at 58 percent weight at 2lb 13 oz,straight up for 25 seconds to 2100ft or so .Why add weight you don't need.Geoff.
Jan 28, 2013, 08:27 AM
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krafty's Avatar
Originally Posted by Geoff Potter
Why would you want to add nose weight to a bombe r or a playboy .Im on Bomber no 91 at the moment and Playboy no 68 and have never had to add weight of any sort or si ze to them .112percent playboy,Thunder Tiger 46 ,balance at 58 percent weight at 2lb 13 oz,straight up for 25 seconds to 2100ft or so .Why add weight you don't need.Geoff.
Wow, that is impressive, the climb rate is 5040 feet per minute. My fairly high powered modern electric gliders only achieve a little over 3000 fpm and approaching 4000 fpm on a good day. See a plot from my RAM logger.
Jan 28, 2013, 04:35 PM
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Paw 60 diesel for CG

Geoff you must have nice balsa. Your “112 percent playboy,Thunder Tiger 46 balance at 58 percent weight at 2lb 13 oz, straight up”. My balsa is not too good and my model is probably about three times the weight of yours!
I just took my Play Boy fuselage down, tail (rudder, fin, stab, elevator) off and weighed it bare, no motor or gear. It’s about 5 lb. In the engine bay area you can see the extra lead weight. Adding either a TT diesel or the MVVS .40 does not bring the bare fuse up to the CG. Adding the PAW 60, just about on CG, but still less the tail (200 + g). The PAW 60 is rather heavy.
Jan 28, 2013, 05:34 PM
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I might have been a bit optermistic there for every flight but generally between 1800and 2100 probably closer to the 1800on a regular basis .The 46 Nelsons and Profi make a mess of me though ,but then my engine only cost me $100 as against 4/450$.I don't select any balsa,just what comes out of the box and thru the bandsaw ,I only by block and cut my own. We have to build to the plan down here NO variations ,so one learns to build lite and simple,if it ain't needed don't put it in,if its tail or nose heavy think of a way to fix it,ya don't add weight,don't lengthen or shorten.When I can get my Granddaughter to do it ill put some pictures on.I also build my own diesels for fun but not in the look at class I'm afraid ,there made to run hard and if they don't they go up in the roof in the junk box,you guys are to pretty for me to put mine on here ..Geoff.
Jan 28, 2013, 07:48 PM
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I hate to brag here, but my FF version built exactly to the plan with a Fox35 up front is right on 32 ounces......2 pounds.
Jan 28, 2013, 09:30 PM
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G'day Howard ,yep one can build light very easily .My standard size FF Playboy goes or went 2 lbs ready to fly with a Mcoy 49 and 2 piece wings ,until Roy and I broke it while trimming it.I hope a photo comes up .The engine was just a head and crankcase I was given and I made the rest. The others all have radio gear.We think we only got one piccy to work wonder why?Geoff
Jan 28, 2013, 09:57 PM
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H ya Geoff. Man made man can fix it. C'mon, you can do it.

I can recall Roy having a plain white Polyspan covered Playboy Snr. a while back, with a Mc.49 in it......or is this it?.....or are there two?????

I often thought a glo Mc.60 in a FF one would be fantastic......if you could trim it of course????

FWIW a bit before Christmas I pulled the Fox out of mine where it's been since 1995, and put a K&B Greenhead Torp.35 into it to give it more grunt for the Vintage Power at the Nats.......kept the thrust line very carefully the same and added a few grams of lead in the very rear to keep the CG where it is at 60%.

Had no chance to give it a fly before the Nats, and of course you would have heard about the wind and the heat in Narrendera so again it never got flown there.

I did fire up the engine though, and on a 10X5 APC it makes a Hell of a lot of noise, and with the exhaust being on the left side as opposed to the Fox on the right side, the exhaust was blowing in my face big time......could be rather exciting on launch.
Jan 29, 2013, 02:37 AM
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krafty's Avatar
Hey guys, I thought this was a "diesel" thread. Still, who cares about that.
You guys are so lucky. In the UK we have no class that allows us to fly big capacity open exhaust motors like the old McCoys and the new Nelsons. I was at the SAM champs at Muncie in 2006 with my little free flight models, but I spent most of my time just watching the big r/c models with these big noisy motors. I was blown away.
Jan 29, 2013, 07:29 AM
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Sorry about that hijack job guys ,one just sort of gets carried away.Im just in the middle of a conversion from glo to diesel on a Russian 46 engine ,Ithink its one of those Map thinggies ,to use as a Texaco motor.have to make a 2 piece head for it and a new hi silicon piston and a 4 mil venturie,hope to get about 6-7 minutes engine run on 10 cc of fuel at about 4500 rpm on a 16 x8 prop.Geoff.
Jan 29, 2013, 10:53 AM
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Thanks Geoff. We all like the info, whether it’s just an engine, or a model with it in. How about a few pictures of what you are building (diesel) and tell us what you are doing. I don’t think too many of us have “machining skills”.
My “little brother” (10 years younger) is an electrical engineer, but got interested in metal working and machining, so he now has a small lathe ( from Sears, 1930’s vintage, can cut threads) and a newer 500 lb modern unit which he got last year. He also made a small foundry to handle molten metal.
I can still remember him flying a U/C .35 stunt model when he was small (? maybe 8 to 10 years old), he needed both hands to hold onto the handle. I had an old 8 mm movie but it deteriorated years ago. Anyway, lots of good memories.
Jan 30, 2013, 05:16 AM
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kkphantom's Avatar
Originally Posted by ohaley
What would be a good size paw engine for 84" Quaker RC Assist?
I had a PAW .35 in a KK Falcon which would be a good deal heavier than a Quaker and it was sufficient power for lazy stooging around
Jan 30, 2013, 02:20 PM
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PAW .60 diesel

This is the PAW .60 diesel. Rather heavy, very rugged.
Even on this carb, the spray bar and fuel line still rotate with the throttle barrel.
I really don’t like the way the muffler has to be fitted to the PAW as it is too difficult to remove. Why remove you may ask. Well, after running, it’s always a good idea to “air out” the cylinder to remove the corrosive residue and then add a little oil. Being able to get at the piston area with a squirt of oil is a lot easier if you can access the area. The PAW .60 rod is fairly “heavy duty”, but not as heavy as perhaps that used on the older OS .60. (Future picture of OS 60 diesel rod). Again, my thanks to Bill A. and John H. for the diesel.
Looking at the previous pictures, you can see that this diesel is even bigger and heavier than the TT, but probably not as much fun ( I may never know). Anyway, here are the pictures.
Jan 30, 2013, 05:24 PM
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John ,how do you put a series of pictures on the thread like you have done on this page .Im 70 odd so will never learn but my daughter and grand daughter who is 16 going on 25 do my high tech stuff for me but when we tried the other day we only got one to stay instead of 3.dont want to hijack the thread again, bit if you can maybe you could PM me ,is that possible here ? Geoff
Jan 30, 2013, 07:20 PM
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Maybe for a little diesel, or maybe just a test run

I’m over 65 too, catching up to you!.

Here’s what I did. ( In addition to letting a little cat out of the bag!!!)


Click on
New reply

Then under attach Files
Click on
Manage attachments

Use Advanced Upload
Select files for upload…from..

This could be your camera card, or a folder for photos on your PC, or from the folder where you have stored the photos..

Select a string by selecting the first file, hold the shift key down and scroll down your list, or
Pick the photos one by one, and when you are done click save.
Wait until status processed says ok,
Then click return to attachment list
You view the thumb nail phot…and also add comments for each one

Save changes
Close this window
Submit reply

And for the rest of the gang, you can help me out if there is an easier way, or please correct me if I made an error, or forgot something.

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