Originally Posted by combatpigg
Stephan..this plane will fly very easily if...
1. The wing loading is low enough
2. The power / thrust is strong enough
3. The model has the correct balance
4. The model has the correct amount of control surface travel
5. The model is assembled geometrically "true" and the controls have no slop or defects.
I have a few biplanes in the size range in your picture. They hand launch very easily with just a slight push away from me. They all weigh about 14 ounces or less.
Any combination of factors that I listed can add up to failure, especially if the .049 engine isn't producing about as much thrust as what the model weighs.
Thank you for your fast reply.
My all up weight (except fuel) is 330 gram (11.6 oz). The engine is a Surestart with the choke 'throttle' and I measured it to 16400 rpm with the 5x3 (?) yellow Cox safety prop. Do you think that is enough power-to-weight ratio?
I have balanced it once, but I will do it one more time just to make sure.
I haven't measured the deflection of the control surfaces - I just made it as big as I could. IIRC I have at least +/- 30 degrees.
Aah, the geometry. Finally a question I have a crystal clear answer to. The slop in the linkage is almost negligible. There are some slop in the servos (yup, I used the cheapest I could find...) but not very much. I would say the wings have some, very small, deviations from the ruler when I hold it against the wing, but I need to hold them against a light to be able so see the error. As for the fuselage it is built using my patent pending Chiquita jig.....
All in all, I know it isn't a perfect build, but I hadn't expected it to fly just a couple of meters. The impression I get (but, given my small experience, it might be wrong), is I need to get the plane up to speed before the rudders have any effect. But hitherto I've hit the ground before I've had the chance to accelerate enough.
It's a good advice you give, practising to put the hand on the sticks in a hurry. As for me, I think I'm above avarage in that aspect because I like to fly with a transmitter glove during the winter and sometimes it gets a bit hairy to get the hand back in there when launching in gusty winds....
Last time I had a friend launching the plane for me, but I will try your method next time I launch myself. Thanks.
Thank you for the picture. Clear plastic sounds heavy. I dont mind the looks of the plane as long as it is functional. Do you think balsa is to soft/weak?