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Tuesday's flying and an engine trim challenge.

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Tuesday's flying and an engine trim challenge.

Post  RknRusty on Thu Mar 26, 2015 12:08 am

I just realized I forgot to post my Tuesday flight report today. But this issue came from Tuesday's flights, so I'll post it here.

My Ukey has a 25fp, the one Jason_WI gave me that used to be on the Osprey. I put a bunch of flights on it and it flew a lot differently than before I fixed the broken nose. Plus I was really rusty from not pattern flying since January. I added some tail weight to bring the balance back, maybe not enough though, so I'll add another 1/4oz next time. I also inadvertently removed some slight but visible down thrust that was no doubt accidentally built in. But it worked nicely before the broken nose with an APC 9x4.

Now I had a lighter than usual pull on the lines and it got worse overhead, and not great even down low. The leadouts are not adjustable. If I ran it lean and fast it was okay but too fast for stunt. So I swapped from an APC 9x4 to an APC 9x6. I didn't have a 9x5 or I would have tried it first. The 9x6 solved all of the control problems. I could run the engine a little wet with a mild and useful  4-2 break(except for a screaming fast 2-stroke during only the outside loops), and still have good pull overhead and a comfortable speed. Just like I wanted it. But it ran out of gas in the second half of the OH8, and had to do a running save... my best landing of the day lol. I'm filling the 3oz tank to the brim already. So I wonder if a wood 10x4 or 10x5 might give me the same punch with better economy. I have plenty of those. I didn't have time to try, but I'm just curious if a 25 will swing a 10" prop with no problem. I have APC and Power point wood props in both of those sizes. I  am glad that I finally got one flight in that I could feel confident from takeoff til shutoff.

I have some APC 9x5 and 9x6 props ordered, so next week, weather permitting, I'll get the answer to my prop vs economy vs thrust questions. Duh, I should have ordered some power point 9x6s too.  I also wonder if the APC 9x6 with 15% nitro rather than 10% would give me the pattern plus 10 extra laps. That's about what I want for practice. I usually try for 7 final laps in a contest.
Rusty

Wayne looking over our fleet




Flight of the Ukey

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Re: Tuesday's flying and an engine trim challenge.

Post  stuntflyr on Thu Mar 26, 2015 12:50 am

Add a little downthrust with some Brodak wedges.
Offset thrust outward just by loosening the engine bolts and scooting it over.
Add a little wingtip weight if it doesn't have anymore tension up top.
Do you make lines and handles for each model? Are they the same as you flew this one before? Are they adjustable?
Chris...
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Re: Tuesday's flying and an engine trim challenge.

Post  Ken Cook on Thu Mar 26, 2015 4:56 am

Rusty, the Ukey is similar to the Gotcha I fly in combat. While your running on suction, I'm running pressure. The fact that the plane has external controls which typically has your lines at a angle from leadout guide to bellcrank. This usually makes the outboard tip fly slightly high. The problem I found with adding wing tip weight on foamies is that the wing wants to severely flop in the outsides. It's hard to change the flight of the wing from one transition to another and the wing due to it's momentum wants to keep going through it's flight path and the wing bounces. I would try and give yourself some engine offset as well. I would note how the plane is flying when the power quits and your gliding in on landing. If the wing is level and the glide path is good, don't add anymore weight. I found flying with Pro-Braid helped many of these models due to the lighter weight of the lines which not only kept the wing level, the speeds slightly increased further enhancing stability. If indeed the plane is floaty on the lines on landing with the outboard wing high regardless of being straight, I would twist that wing outboard high slightly and re fly. This can also be achieved by thumbing your trailing edge high for about 1 1/2" and making a crease. The crease can further be enhanced when you get home and you can iron out the wrinkles giving it a more permanent set. You could also use a bit of 3/4" strapping tape from trailing edge to leading edge. Place the tape on a 45 deg angle pulling a twist into the wing . While this may keep the plane tight on the lines during level upright flight it could do the opposite on inverted. You didn't mention line tension inverted in your post. Is there any stab tilt on that airplane?

I have to question where the leadout guide is located. I found that all of my foamies had a extreme advantage when I used a one hole leadout guide with both lines through the same hole and with the leadout guide just behind the spar. This places the leadout guide forward and keeps the plane from crabbing as it goes up and into the wingover. Adding a leadout guide is a simple thing to do in a foamie. Cut yourself a good piece of ply not lite ply and sink it into the foam with 5 min epoxy. Make a few holes which can give you adjustment and your good to go in minutes leaving the already in place guide.


As for props, I don't care to use 10" props with the Fp. Some claim that the 10x4 works well but I don't care for it as I feel it was loading the engine too much. APC makes a 9x3N which has been working well for me on pressure but I don't know how that would translate using it on suction. I prefer props in the 8x6 range for these on suction but this is going to really compromise your economy.
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Re: Tuesday's flying and an engine trim challenge.

Post  pkrankow on Thu Mar 26, 2015 11:54 am

Sounds like you need to break out your incidence meter and have to check the angles. Sometimes things look off when they are actually correct, and sometimes they look correct, but are quite a bit off.

Phil
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Re: Tuesday's flying and an engine trim challenge.

Post  RknRusty on Thu Mar 26, 2015 12:53 pm

Ken and Mark
The wing has a built in embedded trim tab, and I'll take a look at the leadouts. I want to change them to solids and put them on the bottom anyway. It flies wings-level in both directions. No hinging that I can detect. Maybe a smaller prop with a leaner run. Sounds sensible. I just habitually was thinking 2-4 break without applying common sense.

Chris and Phil
Same lines, .015"x61'. And yes, I make my own line sets. I could use .012" lines but I just don't trust them. I could switch to GSUMP, Spiderwire, etc.
It's a profile, so I have outboard thrust with nylon wedges on top of aluminum pads. I'll address the forward thrust if necessary, but I think it'll be fine straight ahead. If you didn't already know, I'm a very low level intermediate stunt pilot, so many problems originate at the human portion of the system
Gracias, dudes.

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Re: Tuesday's flying and an engine trim challenge.

Post  pkrankow on Thu Mar 26, 2015 7:13 pm

I just reread the rules and I am now confused as to if GSUMP is allowed for competition...

Phil
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Re: Tuesday's flying and an engine trim challenge.

Post  RknRusty on Thu Mar 26, 2015 7:49 pm

It's not, but it's covered by the AMA insurance if there is a mishap while sport flying. I forgot about that, thanks for reminding me.
Rusty

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Re: Tuesday's flying and an engine trim challenge.

Post  Ken Cook on Thu Mar 26, 2015 9:15 pm

Rusty, Phil Cartier is responsible for the use of these lines in both combat and stunt. It is allowed and is covered by the AMA currently for combat. Some mumbo jumbo jargon got criss crossed and the AMA doesn't currently recognize the use of it for stunt. However, it can be used in stunt if  the CD allows it's use and this must be posted on the sanction contest date. So for now it can be used for sport without issue by the AMA assuming you tie the proper knot and use the proper pound test. Ken
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Re: Tuesday's flying and an engine trim challenge.

Post  pkrankow on Thu Mar 26, 2015 9:29 pm

Ken Cook wrote:Rusty, Phil Cartier is responsible for the use of these lines in both combat and stunt. It is allowed and is covered by the AMA currently for combat. Some mumbo jumbo jargon got criss crossed and the AMA doesn't currently recognize the use of it for stunt. However, it can be used in stunt if  the CD allows it's use and this must be posted on the sanction contest date. So for now it can be used for sport without issue by the AMA assuming you tie the proper knot and use the proper pound test. Ken

OK, that is the page I thought I was on.

Phil
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