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Old Nov 16, 2007, 11:53 AM
Micro Flyer "Q"
qban_flyer's Avatar
United States, MD, Silver Spring
Joined Sep 2003
1,390 Posts
Quote:
Originally Posted by l:x
I had another try today: average success. I kept her airborne for several minutes before I attacked a tree...
Result:
- Plane: broken wing and nose that's a bit "smashed"... (All repairable damage!)
- Me: wet feet and pants, strechted muscle and some itchy hands because of some "stingy" weed...

But... I noticed that when I use the rudder, she dives quite hard. Any idea what could be the problem? I have set my expo's on the rudder/elevator so that when I do a "pure" elevator move the rudder holds still.

Greetings,
Niels R.

Plans: This evening I'll try to fix the damage and I'll give her another go in the early morning.
Reducing the amount of throw on the rudder channel will also make it less sensitive on turns and the nosing down attitude will be reduced somewhat; though on all models a certain amount of elevator is needed when making turns.
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Old Nov 16, 2007, 08:31 PM
Curse you Red Baron!
dademoss's Avatar
Cincinnati, Ohio
Joined Aug 2003
12 Posts
Vacation is here, after days of reading I am ready to start construction!

Great thread, thanks to everybody that has contributed!
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Old Nov 16, 2007, 10:30 PM
Postcards From The Purple Edge
tuppertn's Avatar
United States, OK, Sand Springs
Joined May 2007
3,919 Posts
Shweet! Welcome aboard, dademoss. Keep us posted on how the build is going. We're always here if you have any questions.

Quote:
Originally Posted by dademoss
...after days of reading I am ready to start construction!
Really? All 130 pages? Wow!

kendall
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Old Nov 16, 2007, 11:43 PM
Flight Enthusiast
Ferndale WA
Joined Dec 2006
137 Posts
Blue Baby 33" Second Maiden

Quote:
Originally Posted by Tony65x55
Hi Dave. OK, there is possibly more than one issue here. First, do you have a warp in a wing? I'm assuming you have ailerons on this wing... is one aileron rigged lower than the other? If your plane is flying with one wing down it sounds like a rigging issue.

Second, It sounds like you are trimmed nose up. The KFm2 can hit some pretty good angles of attack without falling through the stall. This can be simply remedied with a few clicks of down trim. If your rigging is OK and the CG is OK this is what I would try next.

This isn't that uncommon. My BBAP2 has about 5 degrees negative on the elevator to make the big KFm3 wing groove. Give it a shot and let us know.

Tony

PS: At least you got through your maiden in one piece. The rest is easy.
Hi Tony,
I checked things out per your notes:
1. I built the KFM2 wing flat on a concrete slab and so far as I can see the wing doesn't appear to have any warp.
2. I adjusted the elevator to a little down and on the first toss she went down into the tall grass really fast. Later adjustments to the elevator got a little longer flights but she finally ended up in the same left wing down attitude hanging on the prop. She was actually hanging on the prop with the left wing tip closest to the ground and the fuse at about a 45 degree angle to the horizontal.
3. The ailerons appear to be aligned evenly.
I just can't figure out how to get this baby to fly right. I am beginning to think it is too much plane for me as a pilot without 1000's of hours on the sticks. It is the 33" sport wing with ailerons and no dihedral. Maybe I should build a KFM3 with a small amount of dihedral.
I will keep working on it, but if you have any ideas I sure would appreciate it.
Cheers,
Solar Dave
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Old Nov 17, 2007, 02:30 AM
Registered User
Ipoh, Perak Malaysia
Joined Jul 2006
4,005 Posts
Don't worry about the toss test. The test is just to check for cg problems, not aileron alignment problems, which can be trimmed during your maiden flight, as long as it is not too far off that it will immediately roll over and die in a kamikaze fashion.

chewy
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Old Nov 17, 2007, 04:33 AM
I'm not flying backwards!
Tony65x55's Avatar
Oshawa, Canada
Joined Sep 2004
3,753 Posts
Quote:
Originally Posted by Ferndale Flyer
Hi Tony,
I checked things out per your notes:
1. I built the KFM2 wing flat on a concrete slab and so far as I can see the wing doesn't appear to have any warp.
2. I adjusted the elevator to a little down and on the first toss she went down into the tall grass really fast. Later adjustments to the elevator got a little longer flights but she finally ended up in the same left wing down attitude hanging on the prop. She was actually hanging on the prop with the left wing tip closest to the ground and the fuse at about a 45 degree angle to the horizontal.
3. The ailerons appear to be aligned evenly.
I just can't figure out how to get this baby to fly right. I am beginning to think it is too much plane for me as a pilot without 1000's of hours on the sticks. It is the 33" sport wing with ailerons and no dihedral. Maybe I should build a KFM3 with a small amount of dihedral.
I will keep working on it, but if you have any ideas I sure would appreciate it.
Cheers,
Solar Dave
Dave, I still think you have some kind of rigging problem and the aircraft is sideslipping. Can you post some pics of the plane? Preferrably one straight on the front so I can see the rigging angles, another directly overhead and one of each wingtip. As well, let's check your motor's thrust angle.

In the meantime, it sounds like you are a new pilot (I might be wrong) and I think this wing might be a bit much for you until you get a few flying hours. Build the KFm3 wing with no ailerons and 2" dihedral per side. This will be a much easier plane for you to learn on. After you have a few hours of bombing around like that you can always add ailerons to the KFm3 or put the KFm2 back on and try it again. Cheers!

Tony
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Old Nov 17, 2007, 08:34 AM
Registered User
Belgium, Flemish Region, Mechelen
Joined Aug 2007
45 Posts
Today I had a third try with my BB.
Early in the morning I got out and went to my flying field about 500m from my apartment. I did the whole checklist and double checked once more... I threw up, gave some elevator and there she went...
I've been flying for some minutes when I do an (unwanted) dive due to mis control. It's a bit too much for the wings and they break :s

Result: smashed up nose and broken wings

Went back home and glued with epoxy. Went to do some shopping (bought me a "mobile workshop" to put away all RC tools and electronic parts) while letting the epoxy dry a bit. Taped the wing with some "special" tape and gave her another try...

I've been flying for about 20 minutes and everything went smooth! I made a few landings to calm down from my adrenaline-rush and threw her up again... It was wonderful!!
A shame that she had to live through a series of crashes (which made her a bit ugly) before I could fully enjoy her. The broken wing makes her go left, but I can trim it out.
She has a bit of a "stall" character, but I'll try to figure that one out while improving my flying skills...

Also, a 7x5 prop on my HiModel 282215 1450KV motor might be not the right choice... Maybe a 8x... is a bit better. I've some 9x4.7 laying around, but I don't know if the motor and the 2S LiPo can handle that...

In short: I'm a very happy man! I even don't mind that I had to go to work on a Saturday, because of my successful flight in the morning

I'm starting to build a 100cm BB this weekend with some modifications (mainly battery compartment).

Greetings,
Niels R.
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Old Nov 17, 2007, 09:28 AM
fix-it-up chappie
tolladay's Avatar
Valley Village, CA
Joined Jan 2002
2,262 Posts
Quote:
Originally Posted by l:x
...I've been flying for about 20 minutes and everything went smooth! I made a few landings to calm down from my adrenaline-rush and threw her up again... It was wonderful!!
A shame that she had to live through a series of crashes (which made her a bit ugly) before I could fully enjoy her. The broken wing makes her go left, but I can trim it out.
She has a bit of a "stall" character, but I'll try to figure that one out while improving my flying skills......
Congratulations on getting her up and flying. Way cool!

This happens to all of our "first" flyable planes. I put a Wingo up in a tree, and it was lodged so high, that I couldn't reach it by throwing a baseball or softball. Fortunately a former pitcher was jogging in the park, and came by to investigate. After about 100 throws, and 25 hits, the plane came down in 15 pieces (still some kind of record). The foam was in pieces, the expensive, and hard to replace radio, was just fine. The guy throwing the balls was horrified at the carnage, I was happy, and had her up again 3 hours later, although she was a bit heavier after that with all the epoxy and toothpicks.
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Old Nov 17, 2007, 09:50 AM
Registered User
Belgium, Flemish Region, Mechelen
Joined Aug 2007
45 Posts
Quote:
Originally Posted by tolladay
...although she was a bit heavier after that with all the epoxy and toothpicks.
Hahaha I can imagine... Mine has now some added epoxy-weight too, but I think it's still ok
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Old Nov 17, 2007, 10:09 AM
One of the usual suspects
Vicarious's Avatar
United States, AL, Huntsville
Joined Jun 2007
1,473 Posts
Well, here's another Blu-Baby with a few original ideas thrown into the mix. First, I found a large piece of EPP that was used to ship a server rack tower. I cut and Dremeled this into a 2 inch wide monoblock. Then, I made more monoblock for the aft fuselage, and joined them together. If I were to make another, it would be one solid piece about 2/3 the length of the fuse. I tapered the end going into the tail. I also expanded the battery compartment forward to accommodate some 3 cell lipos that I have. This took out the area for the landing gear, so I used an idea I got from the Dirt Cheap Parkflyer thread. The rest of the build was pretty normal.

I made the original wing - rolling in camber, and adding dihedral with CF struts and epoxy. It was 34" span. It looked great, but...

I made a firewall mount out of two layers of popsicle sticks epoxyed together at 90 degrees. I then epoxyed this to the front of the fuse. This has proven incredibly strong and crash resistant. I used Gorilla glue and Sumo glue everywhere else in the build.

Power is from a BP-21 and either a 1500 or 2000 mah lipo. Too much power? Well, on the maiden filght,it went straight up about 70 feet then was inverted. Did I mention that this is a trainer for me? I actually landed after that one, but on the next flight she took it on the nose hard and bent the motor shaft. The next day I let an experience pilot take the controls. It was very squirrelly - the wing fluttered like a reed valve - and we both decided it needed a better wing.

The KF wing is such an improvement, that I don't think anyone should bother with the old style. Even flat, as mine is now, it is almost self righting. It is gentle and fast. Mine has a fiberglass rod rolled into a crease in the leading edge. It has hit a tree branch with barely a dent. I have read on RCGroups "build to fly, not to crash" but with this I think I have done both. Next, I will be adding ailerons.
Vicarious
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Old Nov 17, 2007, 12:16 PM
Postcards From The Purple Edge
tuppertn's Avatar
United States, OK, Sand Springs
Joined May 2007
3,919 Posts
Vic,

I'm surprised it turns at all on 3-channels without any dihedral. I built a scaled up BB and didn't put enough dihedral in the wing. It did a lot of tail wagging and very little turning. That was a KFm2 wing. Could the KFm3 wing have some characterisitc that allows a flat wing to fly RET without dihedral? Interesting. Tony...any ideas?

kendall
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Last edited by tuppertn; Nov 17, 2007 at 12:24 PM.
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Old Nov 17, 2007, 12:21 PM
Registered User
Saginaw, TX
Joined Aug 2007
26 Posts
Really good looking build Vic. I like your ideas.
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Old Nov 17, 2007, 01:42 PM
Always Ready!
warhead_71's Avatar
Chicago, IL
Joined Dec 2006
5,133 Posts
Quote:
Originally Posted by tuppertn
Vic,

I'm surprised it turns at all on 3-channels without any dihedral. I built a scaled up BB and didn't put enough dihedral in the wing. It did a lot of tail wagging and very little turning. That was a KFm2 wing. Could the KFm3 wing have some characterisitc that allows a flat wing to fly RET without dihedral? Interesting. Tony...any ideas?

kendall
I can fly my 48"KF BluBaby without using the ailerons... and I have less than 1" dihedral. It's a slow gradual turn, but it will turn nonetheless.. and pendulum effect seems to level it out when I release the rudder. I recommend more dihedral if it's 3ch, but it is possible to fly it with as little as 1" on a 48" span.
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Old Nov 17, 2007, 02:51 PM
Micro Flyer "Q"
qban_flyer's Avatar
United States, MD, Silver Spring
Joined Sep 2003
1,390 Posts
Me likes the landing gear very much!

though I would be willing to bet that for a three channel trainer to behave as such, it should have some dihedral regardless of airfoil type.
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Old Nov 17, 2007, 03:01 PM
Registered Aircraft Offender
Truglodite's Avatar
Carmichael, CA
Joined Feb 2007
3,515 Posts
right, it's probably dihedral induced by flex or something like that. nice build btw vic; i like the tapered step, beefy lg, and tapered block. looks rugged, and has some forward thinking built in.

kev

[edit: btw vic, whilst kfm makes for a superior sport wing, the old style wing can be made to work well without fluttering even at 60" spans. of course uc can be more difficult to build compared to kfm, especially when struts are required. still, uc wings arguably have an advantage as far as l/d.]
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Last edited by Truglodite; Nov 17, 2007 at 03:12 PM.
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