First Foamie Built -- F22

[BTCat]

Well, I got the F22 completed this morning. Of course, the wind is over 15 mph and it doesn't look like it is going to get any better until maybe Tuesday or Wednesday next week. I'll put up some pics later.

Even though it was too windy -- I would guess 10 to 15 -- I tried to fly it earlier. Just a couple of attempts. The thing went hard left and nose in both times. Didn't make it more that 15 feet. I don't know if it was the wind, the setup, the trim or all of the above. I do need to reinforce it a little. It is pretty flexible aft of the prop opening. Possibly that would help. Whatever it is, it will be a few days before I can test a fix.

Finished Product:

Foam, Motor, ESC and CF from LHS. The motor is a Tower Pro (link below). I would have gone with the Hextronics that Kent is running or one of the kits Grayson sells. Both probably better choices. The servos are Hextronics HXT900s
www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=4321&Product_Name=TowerPro_Brushless_Outrunner_2408-21#

www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=662

In addition to the CF called for in the plans, take Akent's advise and reinforce the front on either top or bottom. It makes a ton of difference in the flex. (Last Pic)














An 8-4 prop. I'll probably trim the prop shaft. It is at least 3/4 in too long.

[akent]

Humm....

Where is your CG?
Mine is around 17" from the nose of the plane, and about 1" in front of the motor mount.
Some folks were running 16" from the nose, but I found that too nose heavy for me.

Did you put strips of carbon along the bottom strakes?

One thing I learned that helps takeoff is before flying the first time to hold the plane by the nose and give it throttle. When it's at zero G (hovering) state, that's the throttle I take off with. Maybe a touch more.
The torque of the motor will make it veer left with too much throttle. If your motor is a lot more powerful than mine, it could be worse. That is of course without a reversed prop.

Did you remember to turn the prop around so that the lettering is facing forward (towards the motor)? That makes a huge difference on thrust.

You might try some up trim next time.

Good luck!
Kent

[BTCat]

I probably had it throttled up too much. Noob mistake. Also, I noticed my trim was off slightly (3 guesses which way). My CG was about an inch forward of the motor. I measured it a minute ago at ~16.75.

The only CF I didn’t put in (which I added a little while ago) was the CF you had added on the top. I put mine underneath and glued it to the other CF for a little extra stability. Amazing how much a few inches of CF in the front can help take out a lot of flop in the back.

Another thing I noticed when I was playing with the throttle a few minutes ago in the middle of typing this post. It is “weightless” at about 45% throttle. I was closer to 100%. Hmmmm I think you can take the “probably” out of the first sentence

[Solitaire]

Yep, pics BT

As usual, I'm way behind y'all (<--- for the Texans) with the project. No need to indicate how far behind after this next question.

Are you guys using 1.3 or 1.9 weight EPP?

[BTCat]

Mar 6, 2010 16:47:21 GMT -6 Solitaire said:

Yep, pics BT

As usual, I'm way behind y'all (<--- for the Texans) with the project. No need to indicate how far behind after this next question.

Are you guys using 1.3 or 1.9 weight EPP?

I'm not sure which it is. The label is long gone. 1.9 I would assume. That is what I would order.

Pics later today, probably.

[akent]

Actually, it's 1.3 that is more normal, I think.

All of my stuff is 1.3.

Kent

[BTCat]

Mar 6, 2010 18:49:08 GMT -6 akent said:

Actually, it's 1.3 that is more normal, I think.

All of my stuff is 1.3.

Kent

Is 1.3 less dense & lighter? I am assuming it is.

[Solitaire]

Assumption correct.
I guess I'd better get off my butt and get this stuff in the works.

[BTCat]

Mar 6, 2010 22:47:19 GMT -6 Solitaire said:

Assumption correct.
I guess I'd better get off my butt and get this stuff in the works.

Yea, you are almost in last place. I think Dube is about to get into the foam cutting mood also. BTW, I posted the pics above. Nothing special, but its mine

[dubehigh]

looks good bt,

[akent]

That looks great, BT!!
I really like the color scheme! And it will be really easy to see the orientation!

You CG sounds perfect.

I would recommend whacking the shaft off of the motor, so the prop saver can do it's job. As it is, a crash and maybe even a soft landing might bend it.

Aren't those HXT-900 servos amazing things for the price?

What paint did you use?
Kent

[BTCat]

Mar 7, 2010 12:37:37 GMT -6 akent said:

That looks great, BT!!
I really like the color scheme! And it will be really easy to see the orientation!

You CG sounds perfect.

I would recommend whacking the shaft off of the motor, so the prop saver can do it's job. As it is, a crash and maybe even a soft landing might bend it.

Aren't those HXT-900 servos amazing things for the price?

What paint did you use?
Kent

Yea, I was playing with the Towerpro shaft and wanting something better & harder. As I posted in the other thread, the Align 450 SE V1 feathering shaft is perfect. Instead of a "C" clip on the back, I put a screw. The head is large enough to do the job. I ground a couple of flats for the set screws in the front and a couple more for the prop saver screws. The length is nuts on. It goes right to the end of the prop saver.

Paint? Let's see I used scraps and leftovers of rattle cans. I used the fluorescent and different colors top and bottom for exactly the reason you stated -- orientation. The thing almost glows in natural light. Interesting thing about the EPP. It is so porous that if you spray at an extreme angle, almost parallel to the surface, it fills one side of the pores. If you spray the opposite angle with a different color it fills the other side of the pore. It actually changes color with the angle. Cool

I got the HXT-900s for the ailerons on my Super Cub, but decided to use them on the foamie. The work great so far.

[Solitaire]

Mar 7, 2010 7:30:04 GMT -6 BTCat said:

Mar 6, 2010 22:47:19 GMT -6 Solitaire said:

Assumption correct.
I guess I'd better get off my butt and get this stuff in the works.

Yea, you are almost in last place. I think Dube is about to get into the foam cutting mood also. BTW, I posted the pics above. Nothing special, but its mine

Last place is a familiar spot for me.
Finally got the EPP ordered. I couldn't find any better deal than Grayson Hobbies when you consider the freight. I can get depron and blue-cor up here, but nada on the EPP. How stupid is that...having to go to Georgia for supplies.

[akent]

Paint? Let's see I used scraps and leftovers of rattle cans. I used the fluorescent and different colors top and bottom for exactly the reason you stated -- orientation. The thing almost glows in natural light. Interesting thing about the EPP. It is so porous that if you spray at an extreme angle, almost parallel to the surface, it fills one side of the pores. If you spray the opposite angle with a different color it fills the other side of the pore. It actually changes color with the angle. Cool

I got the HXT-900s for the ailerons on my Super Cub, but decided to use them on the foamie. The work great so far.

That is some very interesting info on angle painting! I'll try that on the next one! Very cool! I need to go pick up some of that fluorescent paint for my new one. That is too cool looking!

You know, lots of folks have said that many paints eat these foams. I have tried several different types of rattle can paints and I have found nothing that bothers any of it at all! It makes ya wonder.

Yeah for around $3, those HXT900s are amazing. They should not be confused with the Towerpro SG90 though. The Towerpro's are junk and even cost more!

That motor you have sure sounds interesting. Higher KV and about half the cost of the ones I am running... Who'd a thunk you could buy a reasonable brushless motor for 5 bucks! And hardened replacement shafts available from your heli spare parts bucket!
Kent

[akent]

Finally got the EPP ordered. I couldn't find any better deal than Grayson Hobbies when you consider the freight. I can get depron and blue-cor up here, but nada on the EPP. How stupid is that...having to go to Georgia for supplies.

Awesome, Sol!
I wonder if your LHS would carry some if you asked?

The two LHS's here don't carry it either. It makes ya wonder. In fact these LHS's don't carry much stuff that could be used in a foamie, unless you build a huge one! The Depron they do have is warped and looks pretty old.
Oh well. I am glad that the Grayson's of the world are around.