Ragwing

My Feedback: (2)

Well it has been over a year since I began construction on the Baby bombshell and I finally flew it tonight. It wasn't that I couldn't have flown it earlier, there were just a few things that weren't quite how I wanted. But in any case I gave it a shot.

With a Zinger 7x4 on it the Texaco turned mid to upper 7k, it ran for quite a while (didn't time it). The hand launch went well, and the model started to climb immediately-and wouldn't quit! Sporadically it would abruptly turn one direction or the other, and change pitch as well. This was moderately disturbing because my corrections seemed to do very little in preventing or correcting these turns. It became a bigger problem as the plane was climbing higher and higher making it more difficult to keep track of which way it was flying. There was another sudden turn and the plane went into a spiral, I was panicked, but I remember trying progressively larger movements of the stick, in all directions, to break it free from the spin. It never came out; it hit a ways away from me.

Surprisingly there was very little damage; in fact I had started the engine a second time before I realized that the rudder was broken at its base. The repair will be simple, but I'm wondering what was going on. I was flying by myself, so I don't have to worry about being 'hit'. When I was preparing for the second flight I turned down the rudder rates (thinking the spiral might have been an aggravated Dutch roll), and I added 1/2 an oz of shot to the nose. When full up elevator is applied it is possible that the rudder may move against the elevator. It seems stupid but I didn't check to see that they wouldn't conflict when I set the dual rates, so there is some possibility that the rudder could have gotten jambed on the elevator. I would have thought that my moving the elevator in the spiral would have alleviated any of these problems though. Or perhaps the rudder broke in flight-I don't know. Any ideas?

I really like the way it was flying when it was being predictable, I think I will try an 8" prop next time, just to keep it from climbing quite so quickly. Here are a few pictures, not too exciting but I just got a digital camera ($35-wooo, big spender) so I've been eager for opportunities to use it.

Derek

Lynn S

Do you think the rudder was broken inflight ? The rudder would put it into a spiral dive and if it didn't work, you would have no way to stop it.
Your pictures are very good!!

Ragwing

My Feedback: (2)

Lynn, while you were writing your response I just edited the message to include that point. I don't know if it broke in-flight. It could have, I just don't really know why it would have.

The pictures were taken by my lovely girlfriend, just thought I should insert that

Derek

Remby

My Feedback: (3)

Hello,
From looking at the launch picture, it looks like the engine could use a bit of downthrust, but this could be a "trick" of the picture not showing correctly. How much is the engine ofset? This could help explain the condition you described.
Remby

BMatthews

I can't see the fin being large enough and the tail moment being long enough to cause spiral instability problems even with a rearward CG. The polyhedral would see to that. Besides, I've seen a good two or three BBS's fly locally and they were all as gentle as kittens. I wonder if some sort of ground handling just prior to launch may have broken the rudder link? Unless the fin jammed against something that held it I doubt if just the surfaces touching would make it break. There just would not be that much friction. But if the rudder could be trapped by the control horn back plate or the screws sticking up that would be a different issue.

Now it's possible that with the 7 inch prop and large enough throws on large enough control areas that you may have found the model squirrley. I can't tell from the pics how big the surfaces are.

Oh, and for a $35 camera the shots (at least on the web) look pretty good. I suspect that even Will "Coke bottle bottom" Robinson would approve...

DICKEYBIRD

My compliments to the photographer! Shots 1 & 3 are classic model magazine shots, very well composed.

Sounds like it was gently stalling under power, try some downthrust like Remby said.

Tom @ Buzzard Bluff

We're waiting on the pic of the lovely girlfriend. Preferrably holding the beautiful model.

Try putting the prop on backwards until you get the trim problems sorted out. Reducing the climb may make it as meek as a kitten which will be a clue that downthrust and/or decalage need adjustment. Tom

Ragwing

My Feedback: (2)

Ok, if you insist , sorry, no pics with an airplane (I know OT OT!! string him up by his toenails!!). Janelle, is a senior French major at the college I attend. She is also a budding archeologist and she leaves soon for a nearly 2 month stay at a dig in Jordan, she left for home today [].

Ahem....back to airplanes (she's even cuter than the Baby Bombshell huh?), rog. on the downthrust. I'll put some CA on the tail, a couple of washers on the top lugs and a bigger prop on it and give it a shot. Hopefully it won't get too breezy and I can fly it today. As for the broken tail, it could have been cracked on the ground (it is the weakest part of the plane), and then fluttered in the air. But I know it wasn't fluttering in the prop wash on the first launch.

Thanks for the help guys, hopefully I'll be able to report back later today.

Derek

Tom @ Buzzard Bluff

[quote]ORIGINAL: Ragwing

[quote]ORIGINAL: Tom @ Buzzard Bluff

<Janelle, is a senior French major at the college I attend. She is also a budding archeologist and she leaves soon for a nearly 2 month stay at a dig in Jordan, she left for home today [].>

You exaggerated not one whet. She is a lovely lady indeed. And, archeology being another interest of mine I envy her trip to the Fertile Crescent, I just hope she encounters none of the religious radicals that infest the region.

<I'll put some CA on the tail, a couple of washers on the top lugs and a bigger prop on it and give it a shot. Hopefully it won't get too breezy and I can fly it today. As for the broken tail, it could have been cracked on the ground (it is the weakest part of the plane), and then fluttered in the air. But I know it wasn't fluttering in the prop wash on the first launch.

Thanks for the help guys, hopefully I'll be able to report back later today.>

I'll be very interested in the results. Even though I'm anxious to see how it comes out I will be the first to encourage you to wait for calm wind conditions. I try to contain my urgency to fly a new model until there is no wind to mask the true flying characteristics of the model. It's hard enough at times getting a new model trimmed out without having to guess which of the unwanted traits are because of the model and which are wind induced. Tom

Clean

What receiver were you using? Sounds like a dang Hitec Feather to me, or similar. Works when it's 5 feet away, goes stupid at 6. I had a little Miss Bohemia, not a far design away from a Buzzard, do about the same thing. At 6 feet it twitched, at 15 it was on it's own. After 3 Feathers and the same problems, I switched to one of Hitecs GOOD receivers and all is fine now.

Japanman

B.Mathews.. This is something you have mentioned before- When I looked at the photo I thought- that rudder looks too small- The fuselage having a lot of side area infront of the centre of gravity, and the big prop, I would have thought problems would be caused by to SMALL a rudder.
You have in the past mentioned problems with large rudders, I`d be interested if you could explain why having a too big rudder is a problem and at what point it starts to becomes so.

J.M

Ragwing

My Feedback: (2)

Well the breeze finally subsided a bit so about 15 min before sunset I tried again. And it flies great!

Changes since last time: Rudder is fixed, 3 washers were added behind the top lugs, Zinger 8x4 used. It hand launches effortlessly, and tracks very straight. There was a bit of a breeze starting about 20' above the ground that bobbed it about a bit, but that couldn't be helped. The Baby Bombshell has a great profile in the air, and it was neat to see the sunset glint off of the wings. I flew it for about 15 min after the sun set before packing it up.

Clean: Sorry, FMA Extreme 5, hasn't given me any trouble in other planes.

The engine was giving me a bit of trouble. It would consistently run for about 2 min, before it would quit. I would refuel, though it never took much, and give it another shot. On the last flight I started it back up without refueling and it ran for probably another 5 min, and there wasn't any fuel left. I have a texaco head on it, and 2 or 3 head shims. I'm using 15%, but it is over a year old and starting to turn. In any case I look forward to experimenting with it. I think this is the start of a beautiful friendship.......

But it will have to wait for a month, I leave early tomorrow morning for Alaska and the salmon run. It's not something I've done before, and it will be odd since my capitan is also my best friend since 1st grade, so we'll see how that goes. In any case I'll be back in a month, have fun.

Derek