Emil The Swede

I dont have any experience from an OS-120, but I have a Thunder Tiger F-130. Would be about the same. I did a test a few month ago and got these results (15% nitro):

3-blade Master AirScrew:
14X7: 6,2 Kg, 10000 rpm
15X7:6,25 Kg, 8700 rpm
16X8: 5,2 Kg, 7500 rpm
2-blade Xoar:
16X6: 6,8 Kg, 10700 rpm
18X6: 6,2 Kg, 7000 rpm

(1 lbs = 0.5 kg)

I guess a 16x8 would be fine, perhaps a 17x6.

hombresinropa

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Perfectly balanced at 110mm CG with Master Airscrew 16x8. I got the 14x7 3-blade as well (had it for another plane) just for kicks some day. When I add the spinner it will be slightly nose heavy at 110, so I imagine it would be close to balanced at 107mm.

I think tomorrow's going to be the day. I had to add a TON of noseweight... close to 3 pounds, in addition to the two 2000mah RX batteries. I zip tied everything in place with plywood insulators in between the muffler and batteries, and then gave everything a small dab here and there of CA to keep things from sliding a little. The dabs are small enough that I could use solvent and break them if I wanted to remove the RX batteries or weights, but I thought it would be god to keep things a little more solid up there in the cowl. No CA on any metal parts.

Also looked into DSMX for my DX7, I don't see a need right now, since I don't plan on flying anywhere in the near future where I would expect 100 or more transmitters to be on simultaneously.

hombresinropa

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14.7 pounds, without the spinner or fiberglass scoops.

Firepower R/C

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Dude, the plane is looking good! Remember let the speed build up before liftoff, and climb at a shallow angle!

Good luck, brother!!

hombresinropa

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www.youtube.com/embed/WMWMxqSBkNQ


Run up. We'll see if I have the nerve to maiden it today. I haven't flown in about a year. Taking the electrics out first to get the rust off, then we'll see...

hombresinropa

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[youtube]www.youtube.com/embed/WMWMxqSBkNQ[/youtube]






Run up. We'll see if I have the nerve to maiden it today. I haven't flown in about a year. Taking the electrics out first to get the rust off, then we'll see...

hombresinropa

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I obviously don't remember how to embed the youtube videos, unless they changed something. Hmph. it pops up in the editor...

[youtube]http://www.youtube.com/watch?v=WMWMxqSBkNQ[/youtube]


There we go

hombresinropa

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Well, didn't fly today. Took it to the field with a couple of other planes. Warmed up on the electrics and then taxied the Spit around. Got some wobble in the wheels, looks like the set screw in the oleo wiggled loose. Re-loctite-d everything and will take another whirl tomorrow. I'm also not happy with tailwheel alignment, going to fix that tonight too just to be safe. Engine runs great though... tons of thrust.

hombresinropa

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Emil, did you have a lot of torque to compensate for on takeoffs? how much rudder did you need with your 130?

tevans55

Hombre-

You shouldn't have to compensate alot with rudder on takeoff. The plane is not darty like a sixty size warbird. The plane will definately move around but it is alot easier to compensate for. The difficulty for me was the sensitivity of the elevator because the gear is so close to the CG. When landing focus on the tail because my plane wants to nose over more than any other warbird I have flown. I have it down now but it took a about a half dozen nose over landings to figure mine out. (And one nose over takeoff)

hombresinropa

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thanks, tevan. When I was taxiing yesterday, it was incredibly bouncy, and I did a few runs where I got the tail up and practiced keeping the plane on the main gears without taking off... was a bit nerve racking until one of the set screws came out of the strut and my wheel started wobbling. Nothing bad happened, although some of the loctite seeped into the strut and now it does not compress as freely.

Once I stop wasting time on youtube, I'm going to adjust my tailwheel and get back out there.

I appreciate the heads up, my .40 size spitfire was all over the place on takeoff. I've watched your video a few times, it's reassuring to hear/see that it's stable. It should be, it's a big 'un.

tevans55

You should consider using JB Weld to hold the gear in place. The set screw is probably just to get the gear aligned. On my gear I align the gear with the set screw then put an etch mark on the strut and retract mechanism. Then I JB Weld the strut in place using the set screw to hold the strut in place while the JB Weld dries. I am repairing a friends ESM FW 190 that he bought used and it looks like the previous owner had trouble with his gear due to twisting. Set screws just won't handle the torque the struts are exposed to. I have never had a set of ESM gear but Century Jet tells you to JB Weld the struts in their instructions. If you ever have to take them apart for repair you hit them with a torch and the JB Weld will release in a matter of seconds.

Just a thought!

hombresinropa

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A note on the retracts for anyone who might look on here and be interested in the ESM retracts...

hombresinropa

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Do you mean put JB weld in the hole for the set screw?

hombresinropa

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Here's a picture of the retract. The set screw doesn't clamp down on the retract, instead it's just a "key" for a slot in the strut housing to prevent twists. I think I know what you're talking about, Tevan, and that's something I'm definitely going to do on my electric retracts for my Deuces. This one is different, the gear axle isn't the part held on by the set screw.

To be honest, I have no idea how it came loose. I think it's just crappy hardware.

tevans55

You are correct. I am talking about where the strut joins the retract unit. I thought that was the screws you had come loose. The set screw that came loose on yours is for access to the inside of the strut.

Emil The Swede

I don´t have the  TT F-130 in my ESM Spitfire, it´s in my Hangar 9 Spitfire. In that plane I have to copensate a bit for the torque.

In my ESM I have an OS-200. I has not been airborn yet, due to to much snow here in Sweden, so I can not help you with with the way it handles. I will probably wont fly it until may or june. I will practice a bit moore with my Hangar 9 Spitfire until I´m ready for the ESM. I have only been dooing this fantastic hobby for one year, and I have A few more items to sort before the ESM is ready.

Today I lathe a washer that weighs 300 grams (0,7 pounds) for the propnut to get some moore noseweight, I hope it will work good.

I´m looking forward to here your comments after the maiden and I hope it will go great.

hombresinropa

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Emil,

I see. Thanks for the help so far, I hope it clears up soon over there in Sweden! I got some spinner weight today as well, to ensure I have a good balance after a few more adjustments. I bought a dubro prop hub weight, just like the one you are making.

Didn't maiden it today, either... was at the field starting it up and my helper lost balance and pressed down on the tail... and broke the tailwheel bracket in half. No more tailwheel. &^$@#$&&^%#@!!!! He said it was the bounce from the plane as I was using my chicken stick to start it, but I can't imagine that would have enough force.

So, hopefully I can find something tomorrow at a LHS. Or a not-so-LHS.

Firepower R/C

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You need to get a stooge (I mean the metal kind) to hold the tail.

Emil The Swede

Sorry to hear about the tailwheel bracket. I hope you will find a good replacement. Just be careful with the weight in the tail. 10 grams extra  in the tail probably will give you 100 grams extra nose weight.

hombresinropa

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Rich- I have a home-made stooge, and I was using it. This guy was just in love with the airplane and wanted to touch it I guess, so he was "helping" hold it. I should have known better than to let him... oh well.

Emil- I think I found a replacement OEM tailwheel. there's a guy on RCGroups who lives about an hour from me who is getting the robart retractable tailwheel for his, so I'm going to try and get his off of him. Hopefully,, I'll have it today! It'll be a good excuse to ride around on my motorcycle. if I can get this replacement wheel, then I don't have to mess with weird mods in the back or adding any unwanted tail weight.

Emil The Swede

Sound as a great plan, solving the problem and combining two hobbies. I also ride a bike and have done so for 25 years. I´m still loving it, but if I have to choose it will be RC flight. Fortunately I don’t have to choose.

Good luck in getting the replacement!

hombresinropa

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gear is in the mail, so in the meantime I tried my hand at bending my own replacement wire strut. Here it is. I'm about to install it and see how it goes.

hombresinropa

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Successful maiden! two flights. Home-made gear strut for the tail wheel worked great. Plane had no issues. I just added about 50% expo on the 2nd flight. Flaps gave no pitch tendencies... flew straight as an arrow. Tevan and Emil, your CG tips paid off. 110 - 107 mm is perfect. I didn't raise the gears, so we'll see soon how that affects flight.

No issues with throw, I just added expo but kept the throw as per instructions. took offl ike a rocket with OS 1.20. it's a bit hard to pin the tail on landing to keep it from nosing over, so I'll practice that some more, but all in all, it flew beautifully.

rich, you were right. Giant warbirds fly great. It was 5 mph winds, gusts to 10, and it flew like a dream. I barely even had to trim it after takeoff.

tomorrow I'll get an appropriate spinner screw so I can mount the giant aluminum spinner. I'll also add the fiberglass scoop and blisters. I didn't get any video today, I'll try and get one tomorrow with my mini-cam.

Firepower R/C

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Congrats, Mike! Now get that silly TF Mustang up next... and we all need a video of them both!