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Old Sep 22, 2008, 05:22 AM
Redneck Injuneer
bill34207's Avatar
Bradenton, Florida
Joined Aug 2007
6,355 Posts
I'll have to agree on the bad landing habits and have the video to prove it a couple of posts back. This one has to be flown all the way to the ground, landed "hot" and the touchdown flare just about perfect or it bounces back into the air. Takeoffs are great though and can be very scale like if you go easy on the elevator. It's a good looking model in the air, too.
I'm hoping that as I move the cg closer to the recommended location it becomes more enjoyable in the air as it's not a relaxing model to fly as nose heavy as I had mine. Flying straight you can reduce to about 1/4 throttle and slow it down quite a bit without it doing anything bad. Don't try a slow turn with it though. Even though it's much lighter than it's full scale counterpart, it still displays the "flying brick" characteristics when you slow it down on a turn. I almost crashed mine on my maiden landing approach (not in video) when I slowed it down too much on the final turn.
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Old Sep 22, 2008, 05:29 AM
Rush
Joined May 2007
329 Posts
+1 on that.... you need power to hold the AOA.

Bill.. have you tried running flaperons? Glides in so much better that way. Are you also running the stock servos?

I'm not sure if it was you, but someone posted the need to check the elevator hinging as they get loose after a while. I can confirm this also

Regards,

Rob
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Old Sep 22, 2008, 11:59 AM
Redneck Injuneer
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Bradenton, Florida
Joined Aug 2007
6,355 Posts
Haven't tried mixing in the flaperons yet, but am seriously considering it, and I am running stock "everything" so far. By landing "hot", I meant with the tail still on fire. (power on)
As for the hinges, I noticed one of the ailerons atarting to loosen up while I was still assembling it. Mixed up a little 5 minute epoxy and filled all the holes where they were recessed in.

While on the subject of being mentioned in a previous post... wasn't it you that mentioned oleo struts and it staying planted on landing better with them? If it was, where did you find them?
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Old Sep 22, 2008, 01:38 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
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it looks from the vid to be very nose heavy ,so speed must be kept up to land the thing. i hav'nt read the whole thread ...but why is every one so nose heavy? was there a proplem with the factory C/G setting?
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Old Sep 22, 2008, 05:14 PM
Rush
Joined May 2007
329 Posts
AS - i'm nose heavy cause i'm running bigger packs at the moment so my CG comes to about 4.5". Using FP 3700's and 4250 evolites at the moment to extend my flight times. I get about 5 mins now with a lot of WOT on the HET6904 2w-20 drive unit.

Bill - i got the legs from hobby city. http://www.hobbycity.com/hobbycity/s...idProduct=4681

They're not exactly right for the F4. I had to shorten the total leg lengths to about 70mms, use different wheels which i had lying around and then make adaptor collars with 3mm setscrews so that i could attach the legs to the stock gear wires. Set screws hold them in place. Pics below are a bit small, but i used the stock landing wires.



Regards,

Rob
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Old Sep 22, 2008, 08:29 PM
Redneck Injuneer
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Bradenton, Florida
Joined Aug 2007
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I'll plead guilty to making mine nose heavy on purpose because I didn't trust the assembly manual's specificaton. It called for 165mm (about 6-3/8 inch) from the wing leading edge of a wing with a 14" root chord.
Just a phobia of tail heavy I suppose but when it comes to a delta I like to start around 1/3 of the chord and work my way back a little at a time. You know how it goes, a nose heavy plane doesn't fly well but a tail heavy one usually doesn't fly but once.
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Old Sep 23, 2008, 07:58 PM
LBJ
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Fort Worth, Texas
Joined Nov 2007
702 Posts
Got a new nose made for my F-4. First flight was about 10 seconds. It pitched straight up and then went nose first into the grass. Lucky it just bent the nose and broke the wing tip. I would like to ask what your elevator throws are for this one. I balanced it at the instruction point of 165 mm from LE. I was way nose down before launch CG check. Power was good and it actually climbed a bit before it gave up. I did the hand launch and a friend was doing the first flight to get it trimmed out. Done quite few hand launches, so, don't really know aobut this one. Will try again.


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Old Sep 24, 2008, 05:25 AM
Redneck Injuneer
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Bradenton, Florida
Joined Aug 2007
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Ouch LBJ
Your experience falls into the category of tail heavy planes don't fly far (I think). Or possibly it just couldn't get enough flying speed from the hand launch. Even in nose heavy cg balance it falls out of the air pretty quick if you slow it down too much. Regardless of the HL hype on how well it flies with it's light weight, the design still has much of it's full sized counterparts flying characteristics. It's not nearly as forgiving as say the Hobby People F-16.
I'm using the elevator linkages in the factory positions with 100% throws on high rate and 70% on low rate (30% expo on both settings). I did both my flights on high rates.
My 1st flight was done with cg set at 4-3/4" from leading edge (just to play it safe). 2bd flight (video) was with cg at 5" from leading edge. It still felt nose heavy so will try the next one around 5-1/4". I still think that 165mm (6-3/8") is too far back for a stable flight on a delta wing with a 14" root chord. It may eventually prove me wrong and will continue moving the cg a little at a time until it feels right in flight.
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Old Sep 24, 2008, 04:32 PM
LBJ
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Fort Worth, Texas
Joined Nov 2007
702 Posts
Thanks, bill34207,

I would have thought the CG would have been within specs. But, it deifinitely did a tail stand on launch! Control throws could have been a factor, but they did not seem extreme at the time. I will add some lead to the nose and try again. Maybe 2 ounces to see where that balances out. I had 3/4 ounce on the first flight to make up for the removed gear and servo.

I may call HL to see if they can add any spec changes. They should know about this.
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Old Sep 24, 2008, 06:42 PM
LARKS Lexington RC FLYERS
Joined May 2007
110 Posts
Glad to see not everyone didnt get the award winning poorly built box. Im the lucky winner!!!!!!! Got my wings finally glassed at the joint. The included glue did not do well for me. After 32 hrs I was still able to move the wing back and forth at the joint. So I glassed the joint with 3/4 oz cloth and deluted epoxy. Now just to match the paint. Even installed a few recessed washer in the wings while i had the epoxy out for the wing tanks i had laying around from the great planes l-39. All my servos that where installed moved freely and all the hinging was loose in the wings. the elevators where glued really well tho. if it werent for the big dam gap in them this would of been a high point. All and all its a beautiful jet. but its taken me two evenings now to get this far. Not what i expected. But if its performance is what ive seen on the stock system i will be happy. Let you all know how the maiden goes this weekend. She will be at the flying tigers biggest fly-in of the year in lake city SC. Hopefully it will be a winner and not part of the crash photos for the event.
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Old Sep 24, 2008, 06:59 PM
Redneck Injuneer
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Bradenton, Florida
Joined Aug 2007
6,355 Posts
PlaneNuttz
Glad to hear that you are overcoming the shortcomings and hope it works out well for you. I didn't even open the tube of included glue myself and used 30 minute epoxy on my wings. I just don't trust contact adhesive for that type of connection. With the glass cloth you should still be ok though. Hopefully since yours was not in the best of condition airframe wise you'll have a smooth running fan without having to mess with it.
I've already tested 4-3/4 & 5" CG's for ya so that should save a little time. You might as well start at 5-1/4 as that will be my next move. I think LBJ has already shown us that the 165mm mark is a bit too far back.
BTW I've alnmost completed that JAS39 now.
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Old Sep 24, 2008, 08:42 PM
Got Monica?
CH47FE's Avatar
Joined Sep 2008
70 Posts
noob question. you talk about using 'glass cloth', im guessing thats fiberglass cloth? how do you use it to attatch/reinforce the wings? i used glue on my f18 and i never really trusted it...just looks 'wrong'. Can you steer me to a link or video that shows how to do it?

thanks...
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Old Sep 24, 2008, 08:52 PM
LARKS Lexington RC FLYERS
Joined May 2007
110 Posts
Basically just go to the hobby store and ask for 3/4 oz fiberglass cloth. you can cut this in strips and use 30 minute epoxy deluted with a little denatured alcohol so it will flow smoother. let dry, sand with 200 grit. repeat with a light film of epoxy thinned out again with the alcohol., dry, sand with 200 grit, then finish it off with 400grit sandpaper, clean with alcohol, dry, paint to match. WOOOLAHHHH!!!! 3/4 ounce cloth is the lightest you can go and will give you a super strong joint. mines a rock now.

look at my previous thread. the pic of the wing joint is glassed. will finish sanding tommorrow and paint. if you do it right you can still leave the panel lines intacted.
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Old Sep 24, 2008, 09:01 PM
Got Monica?
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Joined Sep 2008
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sweet, thanks!
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Old Sep 24, 2008, 09:06 PM
LARKS Lexington RC FLYERS
Joined May 2007
110 Posts
BILL34207,

Should be ready by friday. just in time for fly-in. I was gonna go with 5 and 1/2 back to start considering what all of you have tried. thanks for sharing your experience as it has saved me considerable time. I have to say my airframe is solid and true so thats a plus now. Will fire it up tomorrow night and pray the fan and electronics are good. If not its a wash for this weekend. I was so tempted to strip it all down and glass the whole thing and change out the electronics and fan tho. considering i was half way there on the redos and repairs. Just ready to fly this bird!

Thxs for all you help Bill. And the video.



As for the paint, The closest is Model Master RLM 62 green which is too dark. You can add some white to the 62 green and get it very close. But theres nothing out there thats a true match for those out there that may need to know
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