Author Topic: Ship wants to fly at 10ft how to lower (Read 4756 times)

Dennis Toth · « **on:** January 25, 2009, 09:40:19 AM »

Guys,

I've been working with my electric profile for about two months and all the normal trim bugs seemed to be worked out. One last issue is that the ship wants to settle in at 10' for level flight both upright and inverted. The CG is located at the 22% average cord point. I can fly it at 6' but I have to push it down there. Question for the group is there a trim change that I can make that will move the grove down without opening up the maneuvers?

Best, Dennis

Howard Rush · « **Reply #1 on:** January 25, 2009, 10:39:51 AM »

I think Ty's correct. When this happens with my plane, it's because the down line is a tad too long. The plane is already adjusted for incidence and thrust line. So adjust the plane, then adjust the handle.

Matt Colan · « **Reply #2 on:** January 25, 2009, 11:05:56 AM »

Along with what Ty and Howard said, that could do it. Also your neutral could be off at the handle.

Alan Hahn · « **Reply #3 on:** January 25, 2009, 11:36:19 AM »

Maybe it is nervous about the ground!

It is odd that it is high both upright and inverted. Only thing which would affect upright and inverted the same way is that it needs more tip weight and that the outboard wing is high. Trying to think if that would make it want to fly high. Not sure about that.

Howard Rush · « **Reply #4 on:** January 25, 2009, 11:50:19 AM »

I'm sorry. I missed the part about both upright and inverted. Disregard what I wrote above.

Rudy Taube · « **Reply #5 on:** January 25, 2009, 03:05:31 PM »

Hi Dennis,

I forgot to tell you last year about this problem that we have with our ECL power systems. Dean told me that the strong EMF waves caused by the motor's "Flux Capacitor" create an "anti gravity" force to be generated as we get within 2.4 times the wingspan of our ECL planes to the ground. So far, only Egor and Paul W. have found a way to break through this mysterious "Force Field".

I have the exact same problem that you have. Only mine is caused by LDL (Low Skill Level) and there is little hope for a cure. In your case, with HSL, I do not have a clue what would cause this. The only design difference with our ECL systems is that we have a smaller moment of inertia with our lighter front ends (more mass located closer to the CG).

This may be causing you to be able to pull out earlier (with the same amount of pressure input at your handle) than you normally would with a "mass forward" wet plane? Just a WAG. Other than this I don't see anything that the E-power would cause. That is, unless Dean is correct with his explanation above?

Regards,

Crist Rigotti · « **Reply #6 on:** January 25, 2009, 03:42:54 PM »

The problem is obvious. If it's too high both upright and inverted, then you need to make the airplane heavier!

Alan Hahn · « **Reply #7 on:** January 25, 2009, 04:06:44 PM »

Quote from: Crist Rigotti on January 25, 2009, 03:42:54 PM

The problem is obvious. If it's too high both upright and inverted, then you need to make the airplane heavier!

That's easy, just put in a bigger battery!

EddyR · « **Reply #8 on:** January 25, 2009, 04:54:08 PM »

Stuntguy All the above is true but we need to know one thing. When you fly inverted do you hold the handle vertical or do you lay your hand back as most people do. If your handle is vertical when you fly inverted is is a plane problem. If your hand is tipped at a angle I would shorten the down line as Howard said to do.Even when I thought the handle was vertical I have had planes want to fly to high and I shortened the down line and then they were OK both upright and inverted.Just try it and let us know if it works.
Ed

Steve Helmick · « **Reply #9 on:** January 25, 2009, 05:34:48 PM »

I'd still say handle adjustments. Maybe neutral not correct, or too much 'overhang'.

Steve

Mark Scarborough · « **Reply #10 on:** January 25, 2009, 05:48:43 PM »

i want to go a different direction with my thoughts,, I see the handle adjustment, I have seen that too, but not so much when its upright and inverted. With my Gee Bee profile, I know that when I added about 3/4 oz to the nose, the level flight attitude became much easier to hold at 5 feet, before that it wanted to fly level at about 7 or 8 feet upright and inverted. It was not enough to hurt the turn in any way,, and boy did it make it a world easier to fly at 5 feet.
Just another thought to try. If it dampens the turn slightly then you can always open your handle spacing a touch to compensate for it.

bob branch · « **Reply #11 on:** January 25, 2009, 07:02:37 PM »

Denny

The way you build I think Crist has it right. The thing is just too damn light.

bob

Tom Luciano · « **Reply #12 on:** January 25, 2009, 07:46:34 PM »

I'm trying to figure the logic in the handle adjustment. My thinking is, if the handle is slightly off and he has a little up elevator. Wouldn't that make the plane want to dive while inverted? I'm not being facetious here just maybe I don't understand. I'll thank you in advance for straightening me out

Thanks,
Tom

Don Curry AMA 267060 · « **Reply #13 on:** January 25, 2009, 07:48:53 PM »

Duct tape... or is it duck tape. Red Green could fix it with duct tape.

Don

Steve Helmick · « **Reply #14 on:** January 25, 2009, 08:53:21 PM »

Looking at this again. Hmmmm! Well, 22% CG sounds ok, but what is the tail area, in % of the wing/flap area? Ted's Law says that the two percentages should be the same. And, does it have flaps, or no flaps? If no flaps, then 22% is too far aft, generally. How's the glide? What happens when the engine stops? Does the model balloon, or glide slowly and not very far? If so, maybe Mark has hit his head on the nail again!

My thinking was originally that neutral setting at the handle might not be the only thing that applies. If the overhang is excessive, it might make it difficult to make the model respond as expected, especially if the overhang has been adjusted differently, or bias at the handle adjusted, to try to equalize the inside/outside turn response. I have not used handles that had significant overhang adjustment (mostly Tom Morris kit handles, with about 1/4" each eyebolt), so haven't experimented with overhang at all, but mostly, it's bad! I'd say that if you've adjusted the handle to fix inside/outside turn, you should go back and adjust the airplane to fix the airplane's problem, and return the handle to minimal overhang. How about posting a picture of the model, and another of the handle? Maybe there's a clue there. $:-\$ Steve

Mark Scarborough · « **Reply #15 on:** January 25, 2009, 09:22:49 PM »

OUCH!!!!!!!!
dang i need a bigger nail, or a harder head Steve,, lol
Yeah the ower off transition is a really good indicator. However my Gee Bee was totally well behaved on poweroff, but It did get better which translated to better power off penetration, but it was close enough that the ballooning was not obvious. I think its a good place to start, I always TRY to get my cg right before I play handle tweak. Mostly because changing the cg almost always leads to a spacing adjustment on the handle.

Richard Grogan · « **Reply #16 on:** January 25, 2009, 09:30:45 PM »

Quote from: Mark Scarborough on January 25, 2009, 05:48:43 PM

i want to go a different direction with my thoughts,, I see the handle adjustment, I have seen that too, but not so much when its upright and inverted. With my Gee Bee profile, I know that when I added about 3/4 oz to the nose, the level flight attitude became much easier to hold at 5 feet, before that it wanted to fly level at about 7 or 8 feet upright and inverted. It was not enough to hurt the turn in any way,, and boy did it make it a world easier to fly at 5 feet.
Just another thought to try. If it dampens the turn slightly then you can always open your handle spacing a touch to compensate for it.

From everything posted here, this sounds like it could be the situation/cause/fix. Won't hurt anything to ad an ounce to the nose and try it!

John Stiles · « **Reply #17 on:** January 25, 2009, 10:07:53 PM »

I'm beginning to wonder what some of y'all would do if you had to fly on the side of a hill!

Mark Scarborough · « **Reply #18 on:** January 25, 2009, 10:48:23 PM »

John,
I am going to assume that is a legitimate comment, and not tongue in cheek since you didnt use any smiley emoticons,,

I will make a comment based upon why we would want to optimize the trim on our airplanes. In the Nascar top level of competition, Sprint cup, the drivers can drive the cars around the track faster than you or I could even when they are not in good "trim" However, rather than fight with something that requires constant attention, the trim their cars to corner and perform optimally.
We to desire our aircraft to respond as honestly and mindnumbingly honest as possible. In other words, to only require input to deviate from level flight, and to correct for outside stimulus, such as wind gusts or turbulance. And we do fly on hillsides so to speak. i can think of at least a couple contest sites that have slope to them. however, if you are fighting to keep the plane at the right altitude constantly, then it becomes that much more difficult to fly the terrain.

Dennis Toth · « **Reply #19 on:** January 26, 2009, 11:41:39 AM »

Guys,

Lots of interesting comments, over the weekend I did try a few things to see if it is "ME" or if I can trim it a bit better to make life easier. First I tried the easiest that was to move the CG forward by moving the battery (one of the great advantagers of ECL). I move the CG to the 18% point, well it didn't make any big difference in level flight. The corners needed to be hit a bit harder but that's about it. If it were windy it would open up the consecutive and require more control to keep in on track (this is how I got to the 22% point moving it back to get it to hold size in the loops). Next I tried a handle with a negative angle grip, I like to put my thumb on top of the handle and have done so for 40yrs, with the angle handle you need to grip with the thumb down and it really didn't feel good. I then tried a standard hot rock style handle. The HR (now made out of plywood) always had a nice feel to me, it has about 3/4" overhang from the end of my fingers. This handle felt great but the line spacing was about 3/8" more than my Windy handle (also the Windy handle has zero overhang for my hand but feels like the HR). Last shot was to modify the Hot Rock to reduce the line spacing by splitting it open and dremeling in new groves for the wire that reduced the line spacing to the same as the Windy handle. Flying the reduced spacing HR seems really good I need to get more flight time to see if it helps, in flight it seems a little different (I assume it is the extra overhang) but it is very small difference.

One thing that was mentioned was the engine thrust line, mine is set what seems to be 90 deg to the wing centerline but I will put a meter on it to check.

Best, Dennis

John Stiles · « **Reply #20 on:** January 26, 2009, 05:08:04 PM »

Quote from: Mark Scarborough on January 25, 2009, 10:48:23 PM

John,
I am going to assume that is a legitimate comment, and not tongue in cheek since you didnt use any smiley emoticons,,

I will make a comment based upon why we would want to optimize the trim on our airplanes. In the Nascar top level of competition, Sprint cup, the drivers can drive the cars around the track faster than you or I could even when they are not in good "trim" However, rather than fight with something that requires constant attention, the trim their cars to corner and perform optimally.
We to desire our aircraft to respond as honestly and mindnumbingly honest as possible. In other words, to only require input to deviate from level flight, and to correct for outside stimulus, such as wind gusts or turbulance.

When this ice gets off, I'll go down to my flying field and take some pictures....it's pretty hairy

You want to do your loops and conversions on the low side, and get level at about 4' on the high side. I once rigged up a spring loaded system on my elevator pushrod that would self-center....I needed it on the Imperial Ringmaster that had gained weight through too many coats of butyrate dope. I finally put a K&B 40 on it and that was the last flight for that old warbird; all the patchwork over the years was laid bare...I have a video someplace I'll see if I can YOUTUBE it!

Steve Helmick · « **Reply #21 on:** January 26, 2009, 06:03:58 PM »

Whether you Sport Fly or Contest Fly, you should still want to get your model to fly as well as it can, don't you think? Like go where you want it to go, vs. where it decides to go? And have line tension all over the hemisphere, not just put up with whatever you got? Why wouldn't you want to make it fly better, when the better it flies, the longer it will live to fly another day??? We've got a few guys like that in our club ("It's good enough for me!"), and it just makes no sense.

Steve

John Stiles · « **Reply #22 on:** January 26, 2009, 06:21:44 PM »

Quote from: Steve Helmick on January 26, 2009, 06:03:58 PM

Whether you Sport Fly or Contest Fly, you should still want to get your model to fly as well as it can, don't you think? Like go where you want it to go, vs. where it decides to go? And have line tension all over the hemisphere, not just put up with whatever you got? Why wouldn't you want to make it fly better, when the better it flies, the longer it will live to fly another day??? We've got a few guys like that in our club ("It's good enough for me!"), and it just makes no sense. Steve

Dang right I do....one of these days I'm gonna find out what the electric CL is all about....and I'm gonna mothball all my old planes for posterity. I quit once and gave away 20 planes, and went on M/C road trip for several years. When I came back...had to start all over again....I'm not wrecking near as many planes as I used to though, and me and the boys are thinkin about making a bigger field and using longer cables. We can do that now that we are away from power lines. One of my worst crashes was done on purpose due to an induction jolt from the high tension lines. I'm easy to please, and do occasionally make TIC remarks. Don't mind me!

bruce malm · « **Reply #23 on:** January 26, 2009, 07:58:11 PM »

John,
When I first flew some combat at Wittier Narrows, between trips to Nam I kept getting little jolts all the time. That's where I met Phil Granderson.
The fist thing they asked was if I had some copper wire on the handle and of course I didn't.They happily provided a piece that I wrapped around the up line and down around the handle and that got rid of the static jolts. I still have it on my handles and since I have large power lines traversing my property, I still try to remember to put it on all my handles.

Bruce

Tom Niebuhr · « **Reply #24 on:** January 27, 2009, 04:20:41 AM »

Me thinks that you have to do what Howard really does: Step in a hole!

John Stiles · « **Reply #25 on:** January 27, 2009, 08:04:47 AM »

Quote from: bruce malm on January 26, 2009, 07:58:11 PM

John,
When I first flew some combat at Wittier Narrows, between trips to Nam I kept getting little jolts all the time. That's where I met Phil Granderson.
The fist thing they asked was if I had some copper wire on the handle and of course I didn't.They happily provided a piece that I wrapped around the up line and down around the handle and that got rid of the static jolts. I still have it on my handles and since I have large power lines traversing my property, I still try to remember to put it on all my handles.

Bruce

That little red handle with the adjustable cable on the outside will get ya during an approaching storm too. I had to sneak a peak at my palm one day and saw a little spark jump across

We changed to kevlar lines once but I gave them away with my planes.

Author Topic: Ship wants to fly at 10ft how to lower (Read 4756 times)

Alan Hahn

Alan Hahn