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Sep 29, 2011, 10:59 AM
killickb
killickb's Avatar
A deserved article Dan. Are there more than four flying yet? Soon will be I bet! Unfortunately man is not one I subscribe to but hope to find a copy somewhere.

Ps. This is via my new I-pad ---- haven' t mastered the text yet!
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Sep 29, 2011, 03:20 PM
It wasn't me...
DanSavage's Avatar
If there are more than four F-4 models flying they haven't told me about it.

I've sold quite a few, though.

I'm betting that most went into the 'someday' pile like the Su-27/Su-35 kits I've sold.
Sep 30, 2011, 01:12 AM
michigan jet guy
mrshea's Avatar
i have the f-4 on my my work bench. Built from plans and getting the plastic bit's here real soon. Wasn't planning on doing a build log because this one exsist. Only thing i'm doing differnt is fiberglass intakes and trying to see if i can come up with a way to have a scale full flying stab. Phil
Sep 30, 2011, 07:01 AM
Registered User
Daren's Avatar
Phil,

Cool deal on the F-4. Any pictures of your progress?

The conversion to the full flying stab should be a pretty straight-forward job. There's already a plate that the stab glues to that could be used for the pivot mount.

Daren
Sep 30, 2011, 07:53 AM
michigan jet guy
mrshea's Avatar
yeah that's what i figured it's just how to get the angle right, make the mechanism with the angle, and make it strong enough to withstand the speeds without flutter. I have some ideas floating around in my head but i'm going to make a mock up tail to see if it will actually work. No pics yet as i just started and thats alot of parts to cut on a scroll saw. Phil
Sep 30, 2011, 04:58 PM
Big gov never Works
St. Martin's Avatar
Quote:
Only thing i'm doing differnt is fiberglass intakes and trying to see if i can come up with a way to have a scale full flying stab. Phil
Too bad you were not planning on a high power 70mm. I would let you have the intake molds, Phil.

Fuzz
Sep 30, 2011, 06:09 PM
Registered User
Daren's Avatar
Quote:
Originally Posted by mrshea
No pics yet as i just started and thats alot of parts to cut on a scroll saw. Phil
Yah. It's cool that there are a lot of parts, unless you're cutting them out. That's why I opted to be a guinea pig and wait for the first laser kit.

Daren
Sep 30, 2011, 09:05 PM
It wasn't me...
DanSavage's Avatar
Quote:
Originally Posted by mrshea
No pics yet as i just started and thats alot of parts to cut on a scroll saw. Phil
Phil!! Whoa! Talk about intestinal fortitude!

I can sympathize completely as I cut out all the parts for mine, too!

When I got ready to cut my parts, I pulled up a chair, put on some ear plugs, then started cutting.

Dan
Sep 30, 2011, 09:14 PM
It wasn't me...
DanSavage's Avatar
Quote:
Originally Posted by mrshea
yeah that's what i figured it's just how to get the angle right, make the mechanism with the angle, and make it strong enough to withstand the speeds without flutter.
FWIW, as long as the pivot is somewhere around 20% of the MAC, a full-flying stab won't really flutter, even if the stab is not even hooked up to a servo.

I won't go into a lot of detail here, but if you'd like to see what I'm talking about, go to: MiG-32??

Dan
Sep 30, 2011, 09:43 PM
Registered User
LuvEvolution7's Avatar
interesting video Dan and a good discussion of close coupled foreplanes. just a quick question about it...............to get the MAC of a full flying stab, do you still go to the center line of the airplane, as if getting the MAC of a wing, or do you use the root where it meets the fusealge? I'm assuming center line, but just curious. I'm really thinking about this since it's how my Jaguar will be contolled and I believe the pivot point is going to be very similar to the position you found.

Rich
Oct 01, 2011, 12:50 AM
michigan jet guy
mrshea's Avatar
actually fuzz i was strarting to think high power 70mm. I see some of the numbers you guy's are getting with the 70,s and was going to put the airframe on a diet anyways. Just one question will it still rog with the 70? would still like to do retracts as we have an asphalt runway at our club. Phil. And that is another good question rich. I was wondering the same thing myself as to weather or not to use the root measurement or go to the airframe centerline. I don't know if any of you are familar with beanie,s f-100 super sabre in the pusher jet forum but i was thinking of trying a stab control mechanism similar to that.
Oct 01, 2011, 02:04 AM
Big gov never Works
St. Martin's Avatar
Phil, did you see the vid, of mine? NOT lacking in power, and it was only a 5s-3000, HET 6904, ARC 28-48-1.5. Good for 1100W IIRC. https://www.rcgroups.com/forums/show...&postcount=587 4.5 #. Probly not enough power to get out of most grass, but asphalt would not be a problem. The same fan and mtr with a 6s would get you about 1700W.

You could even go with the Eflite retracts or sim. Would add little weight.

I think I'm correct in answering the MAC question. Because your not finding the CG of the aircraft, but the center of aerodynamic mass, No. I always found the pivot point from the root of the stab. First I found the MAC point, then the actual static balance. The pivot tool is just a dowel. Lay the stab on the tool, so the tool runs root to tip and intersects the MAC point. When it balances, the point where it intersects the root, is the dynamic balance point.

I learned this from a glider pilot in the 80's, and used it on a Byrons F-16 first time. They had bad flutter with high power.

Fuzz
Oct 01, 2011, 02:38 AM
michigan jet guy
mrshea's Avatar
yeah i saw that and thats about how i want mine to fly. Fast but not overly so. Alright then i"m going to go with the het 6904 fan and we'll from there but first i have to get these part's cut out. I'll gonna experiment with control mechanism firs before i commit to the flying stab idea first and thanks for the description of how to find where to place things fuzz. Will keep updating as i have things to show. Phil. Edit after doing some research i think i'm going to go with the het 9305 fan insted. Seems to be pretty versatile and and a good fan when it is balanced and assembled right. Phil
Last edited by mrshea; Oct 01, 2011 at 07:47 AM.
Oct 01, 2011, 08:00 AM
Big gov never Works
St. Martin's Avatar
Phil, the 9305 is dynamically balanced. No problems there. The only problem I have had with collet type adapters, is slippage. I take a piece of 220 W&D paper and run the motor holding the paper against the shaft, for a second. This scores the shaft and I have not lost a rotor yet.
On the above vid, Phil, at no time was I at full power. 50% flys it anyway I want. I even have a RBC Panther, that uses the same power system(but with a minifan) instead of the 90mm.1.5-2# lighter than the normal RBC Panther. 8yrs ago, we would have never dreamed of powering these size jets with 70mm fans.

But your choice is a good one. Go with the HET 600 motor with the Kv to suite your desired cell count. Or an ARC motor. Good luck, hope to see some pics soon!

Fuzz
Oct 01, 2011, 10:00 AM
It wasn't me...
DanSavage's Avatar
Quote:
Originally Posted by LuvEvolution7
interesting video Dan and a good discussion of close coupled foreplanes. just a quick question about it...............to get the MAC of a full flying stab, do you still go to the center line of the airplane, as if getting the MAC of a wing, or do you use the root where it meets the fusealge? I'm assuming center line, but just curious. I'm really thinking about this since it's how my Jaguar will be contolled and I believe the pivot point is going to be very similar to the position you found.

Rich
Hi Rich,

Thanks. Nope. Just to the root where the control surface meets the fuselage.

Dan


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