stunthanger.com
General control line discussion => Open Forum => Topic started by: phil myers on February 01, 2012, 11:43:48 AM
-
Hi, I'm in the middle of building a Mercury Cobra with extended wingspan 45" (original was 40). This is a kit that has been cut for me, but I don't have the plans. Can anyone tell me an ideal weight for this plane,its a profile, I'm guessing around 35oz. I plan to use an Enya ss30, will that be ok? Thanks for any replies... Phil
-
This?
Sorry, don't know anything more about it. But maybe someone can guesstimate based on span and the picture.
-
I guess the suggested weight will be o.k.
I always think this Brit. Mercury design could be the Brit equivalent of the U.S. Foxberg event, with a Merco 35 engine. The "MercMerc" event. :-)
-
Hi, I'm in the middle of building a Mercury Cobra with extended wingspan 45" (original was 40). This is a kit that has been cut for me, but I don't have the plans. Can anyone tell me an ideal weight for this plane,its a profile, I'm guessing around 35oz. I plan to use an Enya ss30, will that be ok? Thanks for any replies... Phil
I don't know much about Enyas in general. If its the same as the Enya 30 I *do* know about, it will be adequate but not stellar for this airplane. I would sure try to get it under 35 by as much as practical. If it's a hand-cut kit I would expect the wood to be decent and if so, just eyeballing it, I would expect 30 is probably doable.
Brett
-
I agree with Brett on the weight. I would believe I would try to build it at 30 oz. and be happy if it was 28 oz.
I have no experience with the new Enyas. I have heard the new 30SS is a pretty strong little engine. My old Enya 5224 .35 is a pretty strong .35 for its vintage with the low compression head and the small venturi. Back around 1993 I built a reduced size Impact profile. That engine had no problems pulling the model and I think I must have used 12-15 lb wood for all the construction! (well over 40 oz. LL~ LL~
BIG Bear
RNMM/AMM
-
The SS30 is plenty strong (and not all that heavy). 35 oz wouldn't be a problem for it. I'm planning to use one in a 'Miss BJ', which is 48" and originally used a Fox 35 (I think). I gather it's quite a popular combination in Brazil. (Martin?)
-
The SS30 is plenty strong (and not all that heavy). 35 oz wouldn't be a problem for it. I'm planning to use one in a 'Miss BJ', which is 48" and originally used a Fox 35 (I think). I gather it's quite a popular combination in Brazil. (Martin?)
I am not as concerned about the lack of power as the lack of wing for 35 oz. Particularly if it runs 6" of pitch.
Brett
-
Thats right - Its not about the engines abilty to haul the weight - its about the wings ability to lift the plane at a given weight, in combination with the wee amounts of engine power avaliable to move it forward.
This is in part why a "heavy" 70 oz 600sq plane with a 75 can be competitive but with a ST.46 its not.
-
Thankyou for all the replies, Its a big help, at this stage I don't really know what the finished weight will be but hoped the ss30 would do the job if it turned out at around 35oz. I will try for less.. Forgot to mention this plane will be flapped. I might surprise myself one day and build something light!!
Thanks Phil
-
Thankyou for all the replies, Its a big help, at this stage I don't really know what the finished weight will be but hoped the ss30 would do the job if it turned out at around 35oz. I will try for less.. Forgot to mention this plane will be flapped. I might surprise myself one day and build something light!!
Thanks Phil
Hi Paul,
Building light is simply a mind set. Weighting balsa and using the lightest part that will work.
Also, learning to get finishes light by only applying enough paint to make it right.
BIG Bear
RNMM/AMM
-
Bill, I'll be covering the entire plane with iron on film. The assembled frame (minus all hardware) weighs 16oz, I know the motor is 9oz that makes 25 so with covering, undercarriage, prop and tank, 30- 32oz should be possible. Phil. ps i'm in for surgery today so will reply to any more in a few days time H^^