Sterling P38 kit - good for 049's?

[mccoy40]

Hi all,
I'm not exactly sure where this should go but I'll start here. I have  a Sterling P38 kit that originally called for two .15's - looking att he wing of the kit I though two 049's (cox babe bees) would be more appropriate power for this wing.
The thing I need help with is the balance point. As the kit is now it  would probably be very tail heavy. I could cut some holes in the tail surfaces and the rear fuselage and add a heavier front wheel but is it worth it.

I have a pair of norvel .061's but I think they will be two powerful for this plane.

This might be a good electric kit conversion since the battery could counter balance the tail.


Thoughts? Suggestions?

 

[mike londke]

It will never get off the ground with .049's or .061's. If you want to use small engines get a pair of Cox .09's and build it light. Mike

[dennis lipsett]

It will never get off the ground with .049's or .061's. If you want to use small engines get a pair of Cox .09's and build it light. Mike

Having built a few of them over the years from Fox Rocket 15's in the 50's to OS10's a few years ago I've had a few observations. The 10's were more than the model needed and flew well in level flight with one engine and the model is not critical of which one does the work.
If I was disposed to ever build another one, but I'm not, I'd use 2 Norvel 074s that I have stashed away and would have no problem flying the thing. Remember in todays world it is basically a 1/2A model in wing area and with light wood you probably could fly it with .061 Norvells. Lightness is the deciding factor. Throw half of the kit away and build light and perhaps you could even get it to glide a lap for landing instead if the usual 1/4 lap landing.
Actually for the effort involved the rewards are almost negligible and I'd rather waste my time on something a little more rewarding at the end.

[Paul Smith]

What's the wing span and area?

I built a Grumman Skyrocket with a 25" span and 125 squares.  It goes good on a couple of decent Black Widows.  This is NOT the Black Hawk kit, but a somewhat bigger and stronger model.  

I saw a U Tube of one of these where the outboard wing broke off and went spinning into the weeds with the engine running.  Lesson-learned.  On a twin don't go light on keeping the engines and body together.

[dennis lipsett]

What's the wing span and area?

I built a Grumman Skyrocket with a 25" span and 125 squares.  It goes good on a couple of decent Black Widows.  This is NOT the Black Hawk kit, but a somewhat bigger and stronger model.  

I saw a U Tube of on of these where the outboard wing broke off and went spinning into the weeds with the engine running.  Lesson-learned.  On a twin don't go light on keeping the engines and body together.

Paul,
Not knowing how that Grumman was built is grounds for a lot of questions and doubt. There should be no opposition to light. With small models light is absolutely the prime motivation in building the model. That said a poorly designed model without adequate strength or sloppy assembly by the builder can cause a lot of problems including parts failure in flight. I stand by my comment. If you want a sterling P-38 to fly a lot better that what was put in the box get rid of a lot of that heavy wood reduce the width of the fuselage, go to 1/16 doublers etc., you get the idea. Fly it and then get back to us with your comments on its performance.Just don't expect to do the pattern with it.

[Paul Smith]

A twin has wing-mounted engines that put a lot of stress on the unit.  I don't believe that a multi-engine model will be able to compete with a single on a wing loading basis.  Twins are an impressive novelty, but seldom a  performance success.

[wwwarbird]

Having built a few of them over the years from Fox Rocket 15's in the 50's to OS10's a few years ago I've had a few observations. The 10's were more than the model needed and flew well in level flight with one engine and the model is not critical of which one does the work.
If I was disposed to ever build another one, but I'm not, I'd use 2 Norvel 074s that I have stashed away and would have no problem flying the thing. Remember in todays world it is basically a 1/2A model in wing area and with light wood you probably could fly it with .061 Norvells. Lightness is the deciding factor. Throw half of the kit away and build light and perhaps you could even get it to glide a lap for landing instead if the usual 1/4 lap landing.
Actually for the effort involved the rewards are almost negligible and I'd rather waste my time on something a little more rewarding at the end.

 I had one with two LA.15's at one time. Dennis' above observations and theories are spot on.

[Bill Heher]

I have the kit, and once weighed 2 Cox .09 Medallions, tanks, ply doubles and hardwood mounts, vs a brushless twin set up salvaged from a German ARF Cessna  337 Mix-Master.  The weight was about an ounce heavier for TE electric with battery.

The ARF was about 1.25 meter wingspan and did not feel light. The motors flew it around no problem, vertical was lacking and cruise was about 80% throttle. I think the sterling kit with the fuse pods routed out and the front end trailered for e- power w / throttle would be a fun sport / profile scale, but not a true Stunter.

[frank mccune]

     Hi:

     I have this kit that I built and flew about  years ago.

    Mine has two Fox .15X engines  turning 7x6 props.  It was very fast!  It fl

[Air Ministry .]

Strewth . theres a mauled kit on ebay for 120- bucks .  

You could set the plan up so we can all copy it & the pieces .

Be a devil , use . 15s and lots of nitro .   and maybe 60 ft lines .

what do they fly like ??

[dennis lipsett]

Strewth . theres a mauled kit on ebay for 120- bucks .  

You could set the plan up so we can all copy it & the pieces .

Be a devil , use . 15s and lots of nitro .   and maybe 60 ft lines .

what do they fly like ??

You would do better to get a set of Gary Weavers plans of the P-38.
He basically took the Sterling model and blew it up to 50 inch W/S. He had intentions of putting 2 Fox 35's on it but that is a non issue, Don't even consider it. Two 15's are about right for it and you would be happy with it. Even better the Laser works makes short kits for it for about $50.00.
At the pinnacle is Pat Kings P-38 with a 60 inch W/S and also for 2-15's. Most are not really conscious about how little wing area there really is in this aircraft. I have this kit and it is going on my building table very soon.

Dennis

[wwwarbird]

At the pinnacle is Pat Kings P-38 with a 60 inch W/S and also for 2-15's. Most are not really conscious about how little wing area there really is in this aircraft. I have this kit and it is going on my building table very soon.

Dennis

 Ooo-Ooo! Please keep us posted on this one Dennis!

[Clancy Arnold]

Way back in 1982/83 I built a CL Scale P-38, see the March 1986 issue of Model Aviation, page 75.  It is true scale at 65 Inch WS and was powered by two Super Tigre C35's.  At 500 Sq. In. it flies fast but will fly on one engine. 
Clancy

[frank mccune]

     Hi Again:

     I read my first post and due to sticking keys on my keyboard, my message was a mess.

     What I wanted to say was that the Sterling P 38 kit was very poorly manufactured as the parts did not fit together very well.  The wood was also very heavy.  I covered it in silk and powered it with two Fox .15X engines turning 7x6 props.

     It flew very well, was very fast.  It also flew well on one engine.  I used .015x60' lines.  The sound of a twin in flight is very cool!.  All of this was circa 1980.  I still have the plane in my attic and if I could find some pavement, I would really like to fly it again!

      Perhaps bonus points could be added in Stunt for multiple engine powered airplanes.

     A twin .35 size stunter may be able to take off the thick grass that we have at our field.  As of now, no stunters are able to taxi for a take off on our club field.  Landings are a real thrill to watch. Lol

                                                                                 Be well my friends,

                                                                                 Frank

[Larry Renger]

You can make a nice take-off strip from old political signs taped together with duct tape. Alternate the hinge sides and you can fold it up like an accordion. Mine is 15 feet lonag and I tapered the ends of each sign to make it curve. About 1/2" taper at each end seems to work.

Grab a bunch of the signs after each election!  

[50+AirYears]

I built mine from a Sterling kit, using their die crushed oak parts.  Couple vintage Fox baffle .15s power it, but I still don't have the secret to keeping both engines running.  Needs both engines to get off grass, but airborn, it seems to fly about the same with either engine.  And when they both get quiet, the plane has the glide angle of a space shuttle.  Somehow, I don't think I'd try it with .049s.  But, I have done loops and wingovers with mine.  And it's till in one piece, except for hangar rash.
BTW, I've seen videos of Doolittle flying one, from take-off t landing, on a single engine.  That seemed to include turns both away from and into the dead engine.  The guy knew how to fly.

[Air Ministry .]

but I still don't have the secret to keeping both engines running.

 

Summer Time & the Weathers Fine , sometimes if it hasnt been flown for a WEEK , it'll hold the settings .  


General Proceedure is to remove and blow though Ea Needle , maybe clear residue ? from tanks with a drop of fuel ( flush )
run up and set Ea Motor . Nose straight up , full lean then three ' clicks ' out , and shake the shite out of it , to see if it misses / refine ' running ' setting .  
Miss This -
  and half your flights are wash outs .The big nitro the taps stay on even if theyre fluffing and coughing - where theyd drop out without ' the  light ' .

A Oriental wing gets the nacelles about 14 in apart. being assymetric , the nacelles placed over The Same Rib , get the right hand face ( Thrust Line ) at
HE SAME distance from the fuse centerline. I.E. the CRANKS are the same distance out. The 1/2 sheet nacelles are LEFT of the engines .
To close a spacing gets the prop wash on the fuselage , giving drag / wastage of thrust and turbulance / imbalance . whereas out in the clean air
the thrust on the flaps gets the action on and good control authority . Veco 19 B.R.s are pretty good as far as getting it going . unmuffled .