Good Bye Ol' Iron Ass

[OV10]

Sorry, I couldn't really determine anything from the video
I've got a Great Planes balancer and it has been spot on, so now knowing that yours is not a homebrew machine the only other question that comes to mind is your methodology on how you balance your birds. All low wing craft should be inverted on the stand with gear up, hopefully that's NOT how you did it so as to give explanation to you on the widespread balancing issues. Hope I hit the mark on the cause else if not you have me stumped.

[TSHobbies]

sorry, Im married to the camera operator, so cant fire her lol ..but here it is on the CG machine...exactly same as I flew it last night

[TSHobbies]

[Grossman56]

Now, here's some food for thought, I noticed that the box doesn't give a different weight for the sound system vs the no sound system plane, both boxes say the same (I have both), now, without that sound system, the CG would be different, but the manual says its the same. I smell a rat, thinks I. the cg is probably a little more aft than the one with the sound system. Checked both manuals and they show the same, in fact there is not difference in the manuals both are version No. FW3011-VO1 With OC,(sound system) I balanced her on the little squares in the black stripe on the top of the wing, with the gear retracted, that seemed to work pretty good, then I fine tuned it with the sound system battery( in my case, a 1500 2s from Ol' Weedwacker)
Now, I consider Lon to be the resident expert when it comes to IA with no sound system as he's flown his for multiple seasons, hopefully he'll give his opinion. Meanwhile, I'm going back and check Ryan's video on the plane, he's usually pretty good in pointing things like that out.

Grossman56

[Grossman56]

Ryan is running a 3600 PRO battery and its 1/4 to 1/2 inch back from the furthest point forward on the battery deck, so what I will do is set the battery at 1/4 and then determine from there, where his CG is. It actually should be right where the chord is thickest in the wing, but I'll see what she tells me. I have one coat of Varathane on her and she should be pretty dry, I'll give her one more then see what I think. I use a foam brush to apply it as, to me, it goes on thicker so I don't have as many coats.
One thing, try to avoid the hinges with the clear coat. It won't freeze them permanently, but sometimes they have to be worked loose again.

[TSHobbies]

That sounds like it..I dont know..when it comes to the technical side of figuring out WHERE the CG SHOULD be...I wouldnt know. In reguards to placement of mine..it was on the back line of that little square you mentioned. I removed a couple of washers in the tail I had used to balance it..I'll try it again soon ..and God willing it'll either be fixed, or I can bring it in safely as on the first try...unless someone pops it with another recommendation.

[Aros]

Not to mention the age old question: Balance with gear up or down? I've heard just as many people say gear up because that is your normal flight mode as I have heard people say gear down because takeoff and landing are your most crucial stages of flight and that's where CG counts the most.

For the record, I always balance my birds gear down and NOT inverted FWIW.

[OV10]

Hello Aros,
Your methodology is part of the age old question but, how do you deal with airframes that have gear retracting aft? From my simplistic view of your practice of CG'ing it would have airframes like the P-40, F6F, F4U and A1 all demonstrating very difficult control envelopes when the gear is retracted because the weight shifts aft making it tail heavy. How do you overcome that or do you have a different CG discipline for these type of airframes?
Best regards,

[TSHobbies]

well, I did have it inverted ..and cycled the gear while it was on the balancer..it had no effect

[Lon]

Ryan is running a 3600 PRO battery and its 1/4 to 1/2 inch back from the furthest point forward on the battery deck, so what I will do is set the battery at 1/4 and then determine from there, where his CG is. It actually should be right where the chord is thickest in the wing, but I'll see what she tells me. I have one coat of Varathane on her and she should be pretty dry, I'll give her one more then see what I think. I use a foam brush to apply it as, to me, it goes on thicker so I don't have as many coats.
One thing, try to avoid the hinges with the clear coat. It won't freeze them permanently, but sometimes they have to be worked loose again.

I'm running 3600 40c Admirals, I'm about 5/8" back from farthest point forward. And when i run 5s(450grams), I'm 1 1/8 " back. If i fly then with either battery and i missed my placement mark, i can tell the way the plane handles. And sure enough when i check battery placement after i land. I'm back a little too much from my mark. Now if I go forward pass my mark, no problem, she will fly just a little more nose heavy than what i like.

[Grossman56]

Yeah, good question OV, I wondered that with the P40, Ryan said it balanced up great for him at the fillet line with the gear down (another case of the factory CG being off, nothing unusual). For lack of anything better, I'm going to set it up there. Now with the known information from the video for non sound Iron Ass, I can use his battery placement, knowing that he balances inverted, gear extended, to determine where his CG is. See if that makes sense to me. I use the Great Planes CG machine too, but its only as good as the accuracy of the CG placement if I'm getting this right.

Grossman56

[Grossman56]

Hey, thanks Lon, I was hoping to hear from you
I'm going to Shawano the week of the sixth of June, then heading for anywhere they'll have me to meet some of the fellows, I'd love to get together as Miles is about 5 hour away if the maps on the net are right, interested?

Grossman56

[Aros]

Hello Aros,
Your methodology is part of the age old question but, how do you deal with airframes that have gear retracting aft? From my simplistic view of your practice of CG'ing it would have airframes like the P-40, F6F, F4U and A1 all demonstrating very difficult control envelopes when the gear is retracted because the weight shifts aft making it tail heavy. How do you overcome that or do you have a different CG discipline for these type of airframes?
Best regards,

Good point, aft retracting gear like the Corsair or P-40 you have to be mindful of. I tend to check my CG limits both retracts down and up for the aft retracting gear, making sure I've found a "sweet spot" where there isn't too much of a difference between gear up and deployed.

[Lon]

Hey, thanks Lon, I was hoping to hear from you
I'm going to Shawano the week of the sixth of June, then heading for anywhere they'll have me to meet some of the fellows, I'd love to get together as Miles is about 5 hour away if the maps on the net are right, interested?

Grossman56

Yes i'm interrested...been following the talk. I will seriously make plans to meet where ever here in the upper midwest.

[Lon]

well, I did have it inverted ..and cycled the gear while it was on the balancer..it had no effect

I do the same....get it ballanced, and run the retracts to see the difference. Very little difference with my Mustang.

[Aros]

I maidened mine today even though the prop shaft is wobbly...I figured one flight wasn't going to hurt it much. Holy CRAP was she tail heavy! As soon as it rotated the nose wanted to nearly pitch straight up! Yikes!! I had to slam all the down trim I had just to get her level. Flew her around for about a minute or two tops, plus with it being windy I figured I needed to bring her down before I regret my decision.

Flaps down, slowed to a crawl and I managed a nice clean landing. My CG was placed approximately center of the (-/+) recommended but apparently that is waaaay too tail heavy. So I will move it forward to the front of recommended and try again.

Nothing like a good ol' fashioned knee buckler on a Saturday! :D

[TSHobbies]

so Im not alone here! like I said..thats why its called Iron Ass.. lol..glad you got it down safely though

[Grossman56]

Listen to Lon, 5/8ths back from the furthest point forward in the hatch.

Grossman56

[Grossman56]

Iron Ass got her clear coats today, a little playing around and she'll be ready for the air. I have to get the exhaust stacks painted too so she'll look as good as Old Crow. Both need the gun smoke sprayed on and Iron Ass will need a little work around the exhaust area as well. So, today, the ESC and Motor came out of Old Crow and the 650kv and the Mantis 85A ESC went in. Smooth for the most part, but here are a few things I found. The wire from the ESC is not the one that plugs into the receiver, so don't try to pull the ESC out thinking its unplugged from the receiver because it isn't. Its actually plugged into the little box on the starboard side of the fuse, just aft of the hatch, there are three plugs there, its the top one.
All goes pretty smoothly from there on, its always a joy to work through the rats nest of Old Crow's wiring, and this is after I've gone through and cleaned it up!

So, you get the prop on (which sticks out a little further than it did, not a lot but noticeable) and find that you need a thick washer as well as the stock thin washer that comes with the motor. Okay, found one of those. Good, right? wrong, the screw that holds the prop hub in place is too short now. I found one that was too long and out with the Dremel tool, zip, she's the right size now!
I also took the shims out of the prop as Shirty ran the numbers for me without them and said she was spot on, which is good in Australian! Fair Dinkum Mate!
So, then the old Old Crow parts went into Shangrila, so she now has a 580kv in her. I was going to keep the 70A ESC in her but the bullet plugs are a different size from FW to FMS, go figure! So I just used the 65A that Old Crow came with. The only problem with that is that the wire from the ESC to the receiver is too short so I have to get an extension for her. In the end, that was all I needed. This should be interesting!
BTW, some pics of the warbirds all together, starting to look like my dream museum, I have a Mustang fetish as you can see!

Grossman56

[Aros]

Listen to Lon, 5/8ths back from the furthest point forward in the hatch.

Grossman56

A photo would be fantastic. My fractions suck. LOL!