JB2 Loon

[Catapultguy]

Here is a winter project I’m been playing with.
Not sure how it will actually fly but it was fun.
Has a 64mm EDF in the power pod and I used mailing tubes for the round bits, printed plastic for the transitions.
I haven’t sealed it or dressed it yet. Still thinking how to go with that

The JB2 was the US version on the German V-1 buzz bomb of WW 2. Republic made the airframe and Ford built the pulse jets. According to what I’ve read the US built about 1300 of them for use in the invasion of Japan.

Has anyone else used mailing tubes for aircraft parts? If so what problems should I expect?

 

[Mr Man]

Here is a winter project I’m been playing with.
Not sure how it will actually fly but it was fun.
Has a 64mm EDF in the power pod and I used mailing tubes for the round bits, printed plastic for the transitions.
I haven’t sealed it or dressed it yet. Still thinking how to go with that View attachment 249056
The JB2 was the US version on the German V-1 buzz bomb of WW 2. Republic made the airframe and Ford built the pulse jets. According to what I’ve read the US built about 1300 of them for use in the invasion of Japan.

Has anyone else used mailing tubes for aircraft parts? If so what problems should I expect?

That looks Awesome!

 

[Mr Man]

What’s your AUW and Wingspan?

 

[L Edge]

Very interesting project. I would not worry about the mailing tubes. Concern about the exit area of the EDF. How did you determine that?
If you could, take pics of frontal, top, and exit views as well of giving AUW.

Are you launching by dolly, hand or vertical?

 

[Catapultguy]

What’s your AUW and Wingspan?

36” span and an 8” cord

 

[Catapultguy]

Very interesting project. I would not worry about the mailing tubes. Concern about the exit area of the EDF. How did you determine that?
If you could, take pics of frontal, top, and exit views as well of giving AUW.

Are you launching by dolly, hand or vertical?

Here’s some more pix
Hand launched for first flights
If it flys nice would like to make some sort of dolly or launch rails

As far as EDF particulars most of it is, what’s the phase, winging it.
The raw diameter of the exit tube is just slightly smaller the the EDF but there is the hub of the fan and the diameter of the motor so slightly smaller felt ok

 

[Catapultguy]

As far as the all up weight not really done yet
I do know it is heavier the I planned
Nose is to short for the battery to balance the motor pod

 

[quorneng]

Republic lead the design team but I think you will find it was Willys (of jeep fame) that made the airframes.
If fact 25,000 were ordered to bombard Japan. It was hoped as unmanned missiles it would encourage a surrender to avoid a very costly invasion but the A bomb did it instead.
The order was cancelled leaving the 1300 already built.
My JB2 Loon used a 55mm EDF. has a span of 40"and was made from 3mm sheet foam.

Quite light at 20.5 oz (581g) so a hand launch is no problem but it does require an index finger hole on the underside as the fuselage it too big to grip firmly enough.

To my surprise it flies and glides remarkably well.

I hope yours flies nicely.

 

[Catapultguy]

I will say my Wikipedia research lacked depth. I really hope no one put yours next to mine. It does encourage me to take a bit more care in my finishing.
Has anyone else tried their hand at one of these.
Now making a ramp/rail launching system……..

 

[Catapultguy]

As far as the all up weight not really done yet
I do know it is heavier the I planned
Nose is to short for the battery to balance the motor pod

Ok
I have a problem building anything light. Always seems like I’m over what it says it should be
And I am living up to my reputation. It’s embarrassing actually. Like I said the battery didn’t counter the motor pod like I was hoping. Had to add quite a bit of weight to get the CG three inches from the leading edge.
it’ll be interesting if it flies with any degree of fun. It will need to be fast to get in the air.

Put it off as long as I could it is 1200 grams
About half of that is counter weight to the nose

Thought about removing the nose and stretching it out to lighten it up. I have to see if it’s worth it after first couple of flights

A few weeks to warm enough here in Michigan to play at the field
Let you know when I fly it

Might actually be a cruise missile?!?!?
Let’s keep that part quiet

 

[L Edge]

Possible to lighten tail by:

Cut off some of EDF exhaust duct.
Reduce width of elevator(cut leading edge/width of moving segment )
Reduce width of moving rudder
Reduce width of rear mount or drill holes in structure

 

[Catapultguy]

Possible to lighten tail by:

Cut off some of EDF exhaust duct.
Reduce width of elevator(cut leading edge/width of moving segment )
Reduce width of moving rudder
Reduce width of rear mount or drill holes in structure

Thanks for the feedback

I think the weight of the 3D printed parts were where I went wrong
Didn’t use as light of a plastic as I could and the basic structure of those parts-double walled and reinforcing web between. Way over built.
We see when it’s up in the air(?)
No wheeled dolly attached for the test flight at this weight!!
This is how we learn.

Does anyone know about a foam builder group in mid Michigan?

I would be fun learn from other peoples experiences and maybe share some of my own.

 

[Catapultguy]

That looks Awesome!

Well I finally tried to fly it
Failed pretty spectacularly
Maybe I finally learned my lesson on keeping it light

My other winter projects worked though so I’m hitting 666(not sure that’s a number to be proud of). A fourmation of P-51C’s and a kite wing.