Wednesday, June 1, 2011

Profile F-22 Obsession

I recently came across a thread on RCGroups for a profile F-22 with a wingspan of 18.8in. Ever since , I knew I had to build one. So I did!

The Video




Attempt #1


Originally I only had Home Depot pink foam to work with, so I threw one together out of pink foam.


The CG ended up being pretty far back due to the weight of the foam. Fortunately I found some foam core poster board at the local dollar store, Dollar Tree. The dollar store foam was much easier to work with, so I threw another one together.

Attempt #2


Here are the two planes side by side


The CG with the dollar store foam came out better this time and the whole plane weighs under 220g or less than .5lbs. Awesome, considering the motor is pumping out just over 100W!

The Guts




Notes on the build

  1. You can probably tell that I used gorilla glue. I live somewhere where summer highs reach 115+. My friend had some hot glue melt in his car in May. My planes often end up sitting in my car for hours, so hot glue was out. The gorilla glue is light and relatively easy to work with.
  2. For the stick mount motor, I had to cut out extra foam where the motor mounts. I attached the stick to the side to allow easy access to the screw that holds the motor on.
  3. My goal for Attempt #2 was speed. Not my finest work, but the plane came out ok. Won't win any style or perfectly straight awards, but the thing still flies.
  4. I will probably add some skids, just in case I want to land on a rough surface.

Parts List


I was unsatisfied with my pink foam delta, so I gutted it and threw the guts into this plane. The parts list is nearly identical.

10 comments:

  1. FYI: Gorilla glue is a name brand for polyeurithane glue. Hobbylobby sells Elmers brand, which is a bit cheaper. They also sell a foam glue that dries clear and holds foam really well. Foamtastic I think...

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  2. I knew about the Elmers stuff, but I was eying some foam glue at hobbylobby last time I was there. I'll have to grab some next time I was there. Thanks!

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  3. Where should the centre of gravity be? And would a 2s 1000mah 7.4v Blue lipo work with motor and prop?

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  4. There are plenty of people who fly these with a 2s battery. You will have to pick a different motor, however. This thread has tons of info, including a diagram of where the CG should be,

    http://www.rcgroups.com/forums/showthread.php?t=795691

    Which is about 12in from the nose, or around 4in in front of the slot for the prop. This thing can be pretty squirly with the CG too far back, so err on the side of caution and put it forward.

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  5. I'm thinking about getting a 2200kv motor from hobbyking with a 6x4 prop. I already have a 30A ESC.
    http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=12919&aff=46898

    I made my F22 out of corflute and it weighs 218g with no electronics, with electronics I calculated it would weigh 344.4g. would this fly well with this 2200kv motor from hobbking. Can this plane do barrel rolls with just elevons, and could this motor push a 432g plane good?

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  6. That motor will be plenty powerful. What size plane did you make? The 18in version? I worry that you will have difficulty getting the CG far enough forward. I'm interested to see how your plane fares, post a link to a video of it in action when you try it out!

    As for barrel rolls, absolutely. If you cut out the elevons with the additional surface area, the thing spins like a top.

    ReplyDelete
    Replies
    1. I'm making the 18.8" one, would it be better on 24" one? But it came out a bit heavy. And the bigger motor says it only weighs a couple more grams than the AX 2306N 2000kv motor. And I would put the big motor on a Mugi Evo as well, that weighs 432g without any electronics.

      Are you sure the AX 2306N motor doesn't work with a 2s 1000mah 7.4v 20c blue lipo because in the reviews in hobbyking I saw a guy said he used a 2s battery. Or is it that I have a 7.4v battery? But I thought 1 cell= 3.7v, so 7.4v = 2s, and 11.1v = 3s. Is a 2 cell battery a 2s? Sorry if I'm wrong.

      The epuipment that I bought that is still coming: A 30A ESC 22g, 2x 3.7g servos, deans plugs, 4mm bullet connectors, another AX 2306N motor 47g, 2200kv motor from hobbyking 50g. I already have my reciever 10g. Would this work in both F22 raptor (big or little one) and a Mugi Evo? I plan to make a plane that I can do stunts with. Hopefully both of these planes I will be able to do that.

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    2. I'm a bit confused with the weight of the big motor because they say it weighs 50g and 83g, which one is correct? Hobbyking is confusing!

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    4. Do you need a slight trim to the up elevator so it puts the nose back up because there is no airfoil?

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