Skymaster 1:7.5 F-4 Phantom
07-20-2018, 03:43 PM
#51
Well it flew. Smooth rotation with about 1/2 fuel in fwd tank. Need to work some more on lateral balance and the cg coulfd actually be a little more aft. (About 335 now). Gear only came half up. Put them back down and flew with them down. I found a burned airline after the flight. Landed at TO flaps, just a hair nose heavy but I walked away from it. No damage except airline. Now to get the bugs out and paint.
07-20-2018, 08:35 PM
#52
My Feedback: (13)
Congrats Tom. It’ll be a great airplane just stick with it. Seriously consider bypassing that front tank. It will cut serious weight as well as noseheaviness in the rotation and flare (depending on how you have the plane plumbed).
I always breath a sigh of relief once rolled out on final with the plane. It’s just that solid once established. I have been concentrating on my BV Phantom for the last little bit but need to get the SM back out as it really is impressive
Dave
ps- did you end up doing the scheme for the one you stepped out of?
I always breath a sigh of relief once rolled out on final with the plane. It’s just that solid once established. I have been concentrating on my BV Phantom for the last little bit but need to get the SM back out as it really is impressive
Dave
ps- did you end up doing the scheme for the one you stepped out of?
07-22-2018, 10:22 AM
#58
My Feedback: (1)
I am in the process of rigging the horizontal stabs on my Phantom at the moment. Skymaster recommends two 8711's (480 oz/in each). I am using Futaba S9177SV servos (512 oz/in)
I have been told (by an experienced SM F4 guy) that one 500+ oz/in servo is sufficient for the stab.
His reasoning being that there is no guarantee if one servo fails, that the other one will be able to overpower it since servos can fail in many different ways (although it has been a several decades since I personally had a catastrophic servo failure), and the weight savings could be significant since saving 2 ounces in the tail could eliminate the need for 2-3 times as much weight of lead in the nose.
The servos I am using are SBUS and can be fully programed to match each other, and can be programmed to "free wheel" on loss of signal, so excessive power drain shouldn't be a problem, and the danger (some) of one servo "locking up" and preventing the other one from operating is minimized.
What do other SM F4 owners think?
What size, and how many servos are you using on your F4's stab?
Thanks
I have been told (by an experienced SM F4 guy) that one 500+ oz/in servo is sufficient for the stab.
His reasoning being that there is no guarantee if one servo fails, that the other one will be able to overpower it since servos can fail in many different ways (although it has been a several decades since I personally had a catastrophic servo failure), and the weight savings could be significant since saving 2 ounces in the tail could eliminate the need for 2-3 times as much weight of lead in the nose.
The servos I am using are SBUS and can be fully programed to match each other, and can be programmed to "free wheel" on loss of signal, so excessive power drain shouldn't be a problem, and the danger (some) of one servo "locking up" and preventing the other one from operating is minimized.
What do other SM F4 owners think?
What size, and how many servos are you using on your F4's stab?
Thanks
07-22-2018, 12:12 PM
#60
Call me old fashioned, but I’m going with what the manufacturer recommends. I have 2x8711 in mine. If I built another, I’d also use two servos unless Anton says otherwise.
Last edited by dubd; 07-22-2018 at 07:26 PM.
07-22-2018, 12:56 PM
#61
My Feedback: (13)
I used two MKS 777s. I really don’t think the power is required, but on the *chance* I could bring it home on one I wanted to give it that chance. I ran both elevator leads in a very convenient location so I can unplug them one at a time to check each servo individually
Dave
ps-Thanks Tom. I’ve had a couple times where I’ve said “oh crap it’s today” but was wrong (single engine)
Dave
ps-Thanks Tom. I’ve had a couple times where I’ve said “oh crap it’s today” but was wrong (single engine)
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kwik (01-26-2022)
07-30-2018, 10:35 PM
#72
Kevin put them on the leading edge of the outer door you can recess them in the door slightly then fill in with aeropoxy or with bondo etc. use a second magnet or strip of metal inside the wing skin flange to provide adhesion.
Sorry no pix but can add them later once I make the mod, I like your technique though.
Sorry no pix but can add them later once I make the mod, I like your technique though.
07-30-2018, 10:38 PM
#73
You need to add CF or hardwood blocks to the main gear mounts and aeropoxy the crap out of the landing gear framework. Add CF plate to mounting rails and tap. Get rid of the wood screws.
JMO mind you. The stock setup will work but peace of mind is worth it.
JMO mind you. The stock setup will work but peace of mind is worth it.
07-31-2018, 12:05 PM
#74
My Feedback: (2)
Join Date: Apr 2002
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When I got my kit they changed the aileron and flap horns from external to internal.
I contacted Anton as I was worried about flutter and he told me the internal horns work fine with no flutter reported.
I’ve got 8611’s on the ailerons and 8711’s on the flaps and there is no play but was wondering if anyone has heard of problems.
There doesn’ seem to be any hard points to mount external horns so I hope the present setup is OK.
I contacted Anton as I was worried about flutter and he told me the internal horns work fine with no flutter reported.
I’ve got 8611’s on the ailerons and 8711’s on the flaps and there is no play but was wondering if anyone has heard of problems.
There doesn’ seem to be any hard points to mount external horns so I hope the present setup is OK.
