vh2q

My Feedback: (5)

I put a Cox 049 on the nose of this balsa glider, rigged up with a folding prop circa 7x4. The motor came off a boat (has a heat sink on the head and had a pulley on the drive shaft) and seems to rev lower than the normal Cox 049, which is appropriate for this prop and the reason I selected it. However, it proved to be too wimpy to get this glider going ... it really struggles to gain any altitude. Is there a guideline one can use to determine the appropriate engine size?

Another question: the wings have eye-hooks on their roots which enter through slots in the fuselage when the wings are attached. There are 3 metal rods on each side of the fuse that slide about 4" into the wing. These eye-hooks are not reachable once the wing is on. It looks like they are supposed to be turned a quarter turn to lock the wings in. But no way to turn them. What am I missing here?

OzMo

My Feedback: (3)

rubber band between the screw eyes. Folding props are for electric THEY WILL NOT HOLD UP ON THE 049. Any how I am guessing that s a 100" plane and 049 is a bit small for it, should be fine for a 2 meter bird. Use a prop for a cox 049 and let the motor rev up like 049s are meant to do.
the increased power from the increased RPMs may just make the difference. Have fun but loose the folder and B SAFE

vh2q

My Feedback: (5)

Well landing a glider with a fixed prop motor on the nose seems to me like asking for trouble, even if the motor is stationary. Unless there is a way to ensure that the prop is always east west. And then there's the problem of cavitation pulling a slow glider .... the high rev motors are spec'd for a 3 or 4 pitch prop ... This folder runs fine but I think I am going to step up to a Tee Dee 010. Or maybe I will switch to a Black Widow or one of the other higher performing Cox motors - this particular motor came off a boat I think, it's not spec'd for high revs. Weird looking heat sink on the head ... I need the weight up front so I thought this would be a natural.

OzMo

My Feedback: (3)

Electric props are not designed to handle the output of internal cumbustion engines. Using them on an ICE causes stress fractures at the root of the prop and they will eventually be thrown.
It is an improper use of equipment and not a safe practice.

I don't want to sound combative here, just BE SAFE

BMatthews

By using a 7x4 prop on the .049 you're lugging it down to less than 1/2 the power that it is capable of with a 6x3 prop. And props in air do not cavitate. If anything they stall but with a 6x3 that is not an issue due to the low pitch. And if you set the prop up so that as it just come around onto the beginning of the compression portion of the stroke that the prop is level then it'll tend to stop in theat orientation.

As for whether or not the .049 is enough power can you tell us how heavy the glider is? Generally I would not want to use an .049 on a model that is more than around 30 to 35 oz total weight.