Large Model Association Forum

I am about to start a 1/4 scale D.H. Moth Minor, it's from the Jerry Bates plan. The 110" wing consists of a centre section and two outer panels which join at ribs W1A and W2. I can't find any mention of diahedral anywhere on the plan, other than a Sig SH-724 wing joiner. As I want to make the outer panels detachable, I need to make up my own, longer, wing joiners.

Going off the laser cut parts, the dihedral would appear to be 5 degrees. The distance from W2 to the outer rib W16 is 44 1/2", I've drawn this out and it would appear that rib W16 would have to be propped up by 3 3/4". Does this sound right, or would this be too much dihedral? Any advice would be gratefully accepted. David Jones.

Hi Dave,

I have just finished one of these from JB plan - can't remember what the dihedral is but I'll measure it tomorrow-too wet here at the moment to put it together outside.



Pete

Hi Dave, I have some information in one of my DH books. I will copy and bring to East Kirkby. If you are not going i can email to you.

Dave, I have one which I have flown several times and it flies very well. All I found was that I neede a bit of up trim on the first flight and have the ailerons set up about 2 mm which makes it feel nice and stable. For dihedral it is just set up using the main braces for the center section.
Will try to put a wing on and measure it up for you.
Model uses no nose weight balanced spot on and uses a Roto 25 which has plenty of power.
Will be at east Kirkby if you want to discuss. ( I'm the one with the mike in his hand.)
Cheers
Dave Walker

Hi chaps, thanks for the replies, unfortunately I won't be at East Kirkby this year.
Peter, nice looking model you've got there, what engine did you use and, as far as the dummy hinge line for the folding trailing edge, did you leave a physical gap in the sheeting or is the panel line "cosmetic"?
Dave, same question re the dummy hinge line. Not decided on the engine yet, waiting for the cowl to arrive then we can see what will fit nicely.
Paul, if you have info that you can e mail it would be appreciated, I will PM my email to you, many thanks.

Dave didn't get Cohan early to put it together today - loads of showers.When I do I'll measure the dihedral.

Engine is a NGH 25 flies it well but had to make a new silencer so the cowl would fit - hadn't done it when the pic was taken ,yet to be flown when I fit the cowl.

Model flies well and doesn't need any more power for scale flying,even though the weight came out at just under 20 lbs.

Cheers Pete

Should read - didn't get the weather - don't know where the gobbledegook came from.

I did the dummy hing line as per plan leaving a gap and gluing some dummy hinges (plastic tubing cut with razor saw) in the gap.

Pete

Nice one Pete, thanks for the reply. I've got an NGH 25 in My Apache Chipmunk, not flown with it yet but does seem to be loads of power (replaced an ASP 180 four stroke). I've had a look at some three view drawings of the Moth Minor and there does seem to be a lot of dihedral, so I'm thinking the 5 degrees / 3 3/4" at W16 may well be right. I would appreciate it if you could double check for me when you get chance though. Made a start on the tail feathers for now. Many thanks, Dave Jones.

David, Just had a look at my model this morning, I have attached A couple of photographs which I hope help. Firstly I couldn't get hold of the SIG wing joiner mentioned on the plan so as you can see I used a simple Blade / Box method which is a steel blade into a brass box.

Re Dihedral the plan is a little difficult. The centre wing section is square and the dihedral is built into the inner rib on the outer panel. If you look at sheet 2 of the plan on the extreme Left hand side you will see an item Noted as " Outer 3/32 bich ply Joiner wed " it is this component which defines the dihedral.

Hope this helps

Regards Dave Walker
I have sent the Photo's as a PM

Hi Dave, thanks for that, I've seen the two "joiner web" pieces on the plan, that's where I've got the 5 degrees from, the larger one that fits in the outer panel. I'm feeling more confident that I've got it right. I've PM'd my email address to you. Dave Jones.

Hi Dave ,

Had it together today - my dihedral measures 3 1/2" at the tip from the centre section I.e. rib 16.
Only flown a couple of times to date I'm having problems with the engine - has developed a load of glitching for reasons I haven't found yet - begin to suspect the rxcel box.
However flew well and came in very well for the landing with no sign of tip stall - so must be close.

Hope this helps

Pete

Hi Peter, that's brilliant. I'm confident now that I have got it right so I can crack on with the build. Thanks to everyone for your input. David Jones.