RJ 5 sailplane
 

Has anybody built a RJ 5 sailplane? The real one was made by Dick Johnson in 1950. It was the first sailplane to reach a L/D of 40. He won many nationals contest with it and I'm wondering if anybody made a r/c model of such an important ship. I planning to start one as soon as I collect more information.

RE: RJ 5 sailplane
 

I'm starting to receive information on the RJ 5, it had a 55 foot wingspan. I'm now trying to deceide to make it 1/10 scale which will give me a 65" span or 1/8 scale which comes out to about 82.5". Any suggestions or recommendations? Thanks

RE: RJ 5 sailplane
 

I presume you have seen this short write-up on the RJ5. http://www.sailplanedirectory.com/ross.htm#RJ-5
Designed and partly built by Harland Ross, finished by Dick who made a few changes to the final product.Read somewhere recently that Dick Johnson was killed in a glider crash.
Incidently, have you looked at the line of sailplanes designed by the other Dick - Richard Schreder? I am currently busy building a 1/5th scale RS-15 glider for slope soaring.

RE: RJ 5 sailplane
 

The reason I'm building the RJ 5 is because I was a friend of Mr. Johnson and at his memorial service it was suggested that a static model be built of the RJ 5 for the South West Soaring museum in NM. I thought as long as I'm building a small model I might as well build a radio control one for myself. The original RJ 5 has just been restored to the condition how Johnson flown it in the 1950 Nationals but it is in the National Soaring Museum in Elmira NY about 1200 miles away. Most of the restoration was done on the fuselage and no drawings were created at that time. I contacted the staff at the NSM and they are trying to get information to me. I'm just suprised that such an important ship hasn't been modeled more often. For the NSM I have built a HP 18 for display and have flown other RC gliders. The RJ 5 will be the first scale RC glider that I am building to fly. I'm thinking of building others and would like to have them all the same scale. 1/8 scale would give me a RJ 5 with a 82.5" wingspan but if I build another glider that the RJ 5 competed against, say the Horton IV, that will have about a wingspan over a Hundred inches!

RE: RJ 5 sailplane
 

Locking into one scale might give you fits if you build different scale birds. Why? Because R/C glider performance really is affected by Reynolds effect. And the full scale sailplanes have spans all over the place. So you'll wind up with some that perform well in R/C and some that are somewhat frustrating to fly.

You mention 100" span with an exclamation mark. It's actually nothing remarkable in R/C. The modern high-aspect-ratio models all wind up with long spans. The bottom line is that to get good R/C performance you need to go beyond 2m spans. The R/C performance probably doesn't matter to you very much, but it might matter if you lock into a scale that winds up giving you models that come our with spans less than 2m. You'll be winding up with models that are not much fun to fly.

The advice I'm getting to is that you don't go smaller if you can keep from it. Yeah, you might have to make some longer wings but they're going to be high aspect ratio and if made a smaller scale would have very short chords. But the advice is from a performance perspective. Go smaller and the older birds will really suffer compared to the more modern ones. The R/C performance differences will be way more than the differences seen in full scale.

If I sat down at my drafting board to do that RJ5 today, I'd want to do it to 1/7, just to get the wing almost up to 100". It would have a decent shot a being fun to fly. Of course, it's fuselage would be a handfull, but what the heck.

http://www.sailplanedirectory.com/ross.htm#RJ-5

RE: RJ 5 sailplane
 

I'm thinking 1/8 because if someone want to make a quarter scale rc model all they would have to do is double the plans I created. On the other hand I could just say the models are "box scale" and make them all 100 inch. My aversion to a much larger size model is the fact I have built a fullsize glider and if I'm going to build something big, I might as well go all the way again and start another homebuilt project. That's how I got into fullsize aircraft flying, my dad kept saying my models where almost large enough to fly in. Now I keep the models small enough to travel in the car so if I'm waiting around an airport, I can launch one and entertain myself. Hmmm, a fullsize flying replica....

RE: RJ 5 sailplane
 

Very cool project - I would aim for a 100" span or better to get a reasonable wing loading and L/D. I have seen the original RS-5 at the SSA museum in Elmira. Quite the bit of history!

I was the proud builder/finisher (bought 80% completed finsihed up, and flew for 200+ hours) of a full scale, Dick Schreder designed, HP-18, SN #43, N9040S, contest # E5, in the mid-80's. I would love to see some pics of your RS-15, that was one of my final selections before I found the HP.

Anyone know of any HP-18 R/C kits or plans?

Barry

RE: RJ 5 sailplane
 

Hi Barry
Not much progress lately, but here are pics of where we are. Wing cores cut from insulating foam, and a lost foam fuselage done. Am thinking of turning the fuse into a plug, and making a mold from it. That way I can make more than one fuselage, as opposed to lost foam where you only get one.

RE: RJ 5 sailplane
 

That's great - please post pics as you progress.

Barry

Three view for the Ross Johnson RJ-5 at this link. Soon to be scaled plan for 1/4 scale:
https://www.etsy.com/NewPrairieWoodw...=1612142346942

Rj-5
 

Hi Tom,

Have you had much luck with info on the RJ-5. Have you seen my post on RCGroups I'm building a 1/4 sale replica tail plane finished, fuselage 75% finished cockpit detail; almost done.

Now looking to travl east coast this summer need a site to slope soar it and also PSS models any one got suggestions as to drivable locations as walking is a bit of a problem.

Please if you can send me an email [email protected]

David AKA Da Glider Guy

Tom, I'd be glad to help with your project if not already underway by scaling my drawings to the size you would like. My email is [email protected].
Sounds like a great project. I now have fuselage station point bulkheads included in my three view and can extrude ribs for the wings if you give me profile for the tip and root that you would like.
Tom