Author Topic: FA flight report (Read 4647 times)

minnesotamodeler · « **on:** July 09, 2007, 03:12:12 PM »

OK the Frankenstone Arrow has had its baptism of fire. Had it up several times today, pretty interesting:

First, you may recall I had some problems keeping the engine running before. Sad news, guys, the cowling is the problem--engine just wasn't cooling inside. Below is a couple of pics of the successful flying configuration--no cowl, tank compartment sealed with foam, rubberbanded in. Engine ran and needled fine with this setup.

Next problem: Remember I had added a tail wheel, putting the ground attitude nearly level--made it look really good. Well, first flight, it came off the stooge with the .061 just singing away as it does, taxiied nicely...and taxiied...and taxiied...a fast taxi, but stuck firmly to the ground. I kept increasing control until I had it on full "up", you could clearly see that big ol' flap in back sticking up, and it was still on the ground! A full quarter lap, then I ran out of pavement and hit the grass lip--plane kinda bounced, and suddenly it was doing a VTO. I had short-tanked it so didn't do much, just ran it out and got it back down--by the way, landing is what it does best, just lovely. It evidently LOVES being on the ground.

Obviously it needed some positive AoA on the ground to get airborne, so I bent the tailwheel up and back to lower the tail. Also moved the leadouts back a little since it seemed pretty light on the lines. Next launch was much more "normal", off in maybe 15'. Second problem solved.

Well, I gotta tell you guys, this plane is SLOW! I was amazed; the .061 is plugging away as it does, sounds good, nice rpms, yet the plane is just lumbering along--best I could count, without a watch, easily over 5 sec. laps, maybe close to 6. Admittedly this is on my 48' lines, but I really expected this thing to be fairly fast--huge wing, 10.5 oz., should equal a really flat AoA and good speed. Well, it's flat, but slow--lumberingly slow. I guess all that wing area = a lot of skin friction. It was like I was towing a parachute, or something.

I did take it into some cautious maneuvers, which it handled OK considering. If you've ever flown a Wow, or Half-fast, then you know how it flies--just slow it down a lot and you've got it. It is prone to stagger with just a little too much control input, and there ain't much between "not enough" and "too much".

I'm really not sure what to do with it--according to the plans, it balances 'way noseheavy, but certainly doesn't fly like it--I'm not inclined to move the CG back any since it verges on unstable as is. One thing: Next time it flies, it'll be on 42' lines; I may even try it on 35'. And I guess too I could try a 5x4 prop or so to try and get some airspeed.

One positive note: If there's ever a "landing" contest this plane should win it hands down. Floats down nice and slow, slower, slower...then grabs the ground like a magnet and sticks to it. No bounce whatsoever even if you "rough" it in a little--thanks to Frank's aluminum gear, it absorbs shock by bending, not springing! I never saw a plane that likes its wheels so much.

Roger Vizioli · « **Reply #1 on:** July 09, 2007, 06:33:56 PM »

Ray,
I also thought it would be faster.
Are you using a 6x2 prop?
Any idea of engine speed? (I think I remember you once saying, " Tach, what tach?")

Roger

Ralph Wenzel (d) · « **Reply #2 on:** July 09, 2007, 09:28:48 PM »

In addition to prop, what fuel and which .061? There's a world of difference between a BigMig on 10% Nitro and an AME on 25%!

minnesotamodeler · « **Reply #3 on:** July 10, 2007, 08:11:26 AM »

Ralph, I don't have any AMEs, it's a BigMig .061, 15% fuel, APC 6x2 prop, 48' lines. The exact same setup carries my LittleAxe, same weight, 2" longer span, full-bodied standard planform, under 4 sec. laps unless I run it really rich. On the FA, singing along at peak, it's pushing 6 sec. laps.

Roger, I don't have a tach, but it was producing typical runs for the engine, something over 20,000 I'm sure. Running without the cowl does make it pretty dirty dragwise, but still it seems abnormally slow.

One obvious step I guess is to try an APC 6x3, it'll still fit in the spinner. You recall, this is a slightly enlarged version from the plans, since Ruschke's design called for an .049. I wish Frank would finish (and fly) his stock version so we could compare.

If you ever put a too-big streamer on a too-small combat plane, you know the sensation: Plenty of power from the engine, but the plane just has its brakes on. That's OK as far as it goes, if it handles the low speed OK, should actually make for a better stunt plane. Maybe it's just a matter of my getting used to it. As I said, shorter lines should help.

It's put up for now; I'll try it again with the variations mentioned, another time. Gotta make some major mods to the cowling, maybe remove most of it around the cylinder. Looks kinda goofy without it.

--Ray

Roger Vizioli · « **Reply #4 on:** July 10, 2007, 08:59:57 AM »

Ray,
I believe I tried a 6x3 APC on the old 1/2A P'finder and did not like the performance. Cant remember details as it was a few years ago, but I believe it loaded the engine more than it liked. Been using/been happy with the 6x2 ever since.
Roger

minnesotamodeler · « **Reply #5 on:** July 10, 2007, 12:16:24 PM »

Yup, the APC 6x2 is about the perfect stunt prop for the Norvel .061. For sport or combat, etc., a Cox narrow-blade 5x4 works very well too, or the APC 5.7x3 ain't bad either. I was using the 6x3 on my heavier LittleAxes before the current one (15-16 oz.) and it pulled it pretty well, but it did seem to keep the Norvel a little below its preferred rpm range. Maybe with mucho nitro it would work as well as the 6x2.

Roger Vizioli · « **Reply #6 on:** July 10, 2007, 02:11:11 PM »

Hmmmm.
Frank, awaiting flight test results on your "std size" 1/2A FA.
I might have to build a new nose and use my Norvel .074.
Roger

minnesotamodeler · « **Reply #7 on:** July 10, 2007, 05:57:50 PM »

That had occurred to me, Roger, I didn't know you had one but an .074 might work well in it. Mounting holes don't match, huh? Too bad.

Roger Vizioli · « **Reply #8 on:** July 10, 2007, 07:15:16 PM »

Ray,
It's more than mounting holes.
Weight: .074 w/muffler = 80 grams, .061 w/muffler = 54 grams (.074 about .9 oz heavier)
Beam mount spacing: .074 = 7/8", .061 = 11/16" .
Would need to shift engine and tank further aft so as not to have to add tail weight.

I'd rather see a solution for using the .061.

Roger

minnesotamodeler · « **Reply #9 on:** July 11, 2007, 03:43:36 AM »

Yup, one thing this plane doesn't need is more weight, especially in the nose.

Let's see what it does with a faster prop and shorter lines.

Might be a few days now since I seem to have picked up a stomach bug.

--Ray

frank carlisle · « **Reply #10 on:** July 11, 2007, 03:50:41 PM »

Ray, I just found this thread. Congratulations on getting your Arrow into the air. You gave a very good report. It's a little disheartening that the cowl had to be removed, I hope mine works o.k. as is.
I haven't made any progress on my standard Arrow. The summer has been full of regular modeling adventures. I had real problems with the engines for the LA Heat. It took 4 engines to come up with two. One engine wound up with a broken con rod so I got set back with starting the whole break in process over again. Another engine just wouldn't run right. I finally bolted them to my profile Pathfinder and worked out the issues by flying and trying. Finally wound up using muffler pressure, uniflow tanks, 10/5 or 4 APC props. While all this was going on I did some contests and went to Brodak. Made a couple DVD C/L movies and broke the vertical fin off the Heat just moving it around. I just got primer on the repair. Hopefully that monster will be ready to fly by Sunday.
I learned a new trick with my Bi-Slob and can now hover it in one spot for the whole flight. That trick cost me a siezed up Fox .35. I took the Fox off of a profile Mustang I hadn't flown in years and put it on the Slob. I then put a Brodak .40 on the Mustang. Now I am prepping the Heat for it's maiden flight and hopefully a mid season run of contests with it.
Oh .....I can now sit in a lawn chair and fly the Bi-Slob, I can lay on my back and fly it too.

minnesotamodeler · « **Reply #11 on:** July 11, 2007, 09:45:06 PM »

Bout time you chimed in, Frank...I figured you were gallivanting around to contests and such.

That is one gorgeous Mustang. Does it fly as well as it looks? But I don't know why you're so stingy with the stars, surely you could fit a few more on there...

So the Bi-Slob is the lazy man's plane, now I see. I have flown a combat wing laying on my back but I can assure you it wasn't intentional! Nor for very long. Things happen in the combat circle...

Flying that LA Heat has been a long time coming. Sure hope it lives up to its billing. I think multiple engines are kinda like multiple kids, the trouble increases as to the square of the number--i.e. 2 engines = 4 times the trouble, etc.

You are gonna get some video of its maiden flight, right? For those of us experiencing vicarious thrills through you?

--Ray

frank carlisle · « **Reply #12 on:** July 12, 2007, 12:56:46 AM »

Hi Ray,

It's been a hectic summer around here for sure but I'm sure it's that way for you too.
I saw the little coraplast Barndoor and the models the girls built. And I've tried to follow what you and the other guys are doing. It's easier in the winter time since we're housebound to a much higher degree.

Your FA looks really cool.

Bill Little · « **Reply #13 on:** July 14, 2007, 08:01:37 AM »

HI Ray,

Sounds like you do need more pitch. And it sounds like the .061 doesn't like to keep a 6" diameter and go up in pitch. The 5.7X3 or trimming one to 5.5X3 might just be the ticket. The plane IS flying way too slow for stunting. And, as you know, going down in prop diameter does help cornering.

minnesotamodeler · « **Reply #14 on:** July 21, 2007, 02:50:25 PM »

Here is the modified cowl so the engine will cool...I hated cutting that pretty front off of it but would hate worse a cooked engine.

Without the front end overhanging the holddown screw, the aft end was free to lift. I had to put a dowel-and-keyhole back there to hold it down. (Forgot to get pics of that, sorry. Just a 1/8" dia. dowel projecting out of the cowl, and a 1/8" hole in the ply. former it butts up against.)

Ready to try again with 5.7x3 prop and 42' lines. Report pending.

--Ray

frank carlisle · « **Reply #15 on:** July 22, 2007, 07:01:39 AM »

Nice job on the cowling mods Ray. It looks like original parts. No cooling problem now I'll bet.

minnesotamodeler · « **Reply #16 on:** July 22, 2007, 03:20:53 PM »

Well I appreciate the good words Frank, but it was painful cutting the front off...I worked hard on sculpting that nose. Shows I have a lot to learn about cooling ductwork (or whatever the term is). Guess I need to hang around some Speed guys or something.

But that spinner sure looks good on there, doesn't it? Tell your buddy "thanks" for me again!

--Ray

Clancy Arnold · « **Reply #17 on:** July 22, 2007, 07:18:13 PM »

Ray
Sorry I did not look at your over heating problem before you shortened the cowling.

It appears to me that you have two problems. Cooling air in and hot air out.

It looks like the front vent is just big enough and fitted to the venturi intake. You also needed a second hole higher up to vent air to the front of the cylinder area. You also needed a vent to allow the hot air to exit out from around the engine. This is some times done by making a scoop shaped notch behind the engine that goes down to the cylinder cooling fins.

Clancy

minnesotamodeler · « **Reply #18 on:** July 22, 2007, 07:40:01 PM »

Well Clancy, I was trying to be clever with my louvered vent underneath for hot air out...obviously didn't work. The front cool air vent was bigger than the venturi, but again obviously not big enough. I probably won't mess with full cowlings again, just don't know enough about them.

--Ray

Bill Smith · « **Reply #19 on:** July 22, 2007, 08:14:19 PM »

Sorry I haven't been around in a while.
My large FA flies on 45 to 50 ft lines with 25% nitro all synthetic and a 5.5 x 2 apc prop.
my lap times are 4.7 to 5 sec with a .049 big mig and my plane is heavier by a few ounces.
I can't remember what RPM's I am getting I just let it rip and then back off the needle till it drops just a smig.
I have never had a .061 but I think it should pull you're plane a lot better that that.

minnesotamodeler · « **Reply #20 on:** July 22, 2007, 08:22:36 PM »

Bill, I thought so too. Maybe flying with the cowling off produced a tubful of drag. I'll take it out again with the modified cowl whenever the weather permits.

How large is your "large" FA? Mine is 34" span. Ruschke's original plans show 30", I think.

--Ray

Bill Smith · « **Reply #21 on:** July 22, 2007, 09:16:02 PM »

35.25 and is a little over 13.5 ounces. I think the extra weight on mine tames it down a little but it is still flown on a combat handle. floats nice.
I don't think there should be that much drag from the cowl removal.
This might be a dumb question but is it possible that with the heavy nose the plane is crabbing out and scrubbing off speed??

Roger Vizioli · « **Reply #22 on:** July 23, 2007, 06:44:02 AM »

Ray,
Do you have some smaller (dia and width) and lighter wheels you can use next time out?
Drag from those wheels high.
You mentioned it was sensitive.
Their location, well below the cg, also contributes to negative (down) pitch.
Just another "thought".
Roger

minnesotamodeler · « **Reply #23 on:** July 23, 2007, 08:42:11 AM »

Bill, although it static-balances 'way ahead of the plan indication (an inch or more), it doesn't fly noseheavy at all, no noticeable yawing out. In fact I moved the leadouts back some because it was a little light on the lines. And it turns OK in maneuvers, just kinda shaky because of the low airspeed; is definitely susceptible to overcontrol.

Roger, the wheels are those cheap two-piece hollow plastic things, weight negligible. Some drag there for sure, but remember I'm flying on grass, not very well groomed at that. Gotta have the diameter. Total weight, with its post-flight sheen of castor, just under 11 oz.

Could be part of the problem is just perception, I'm maybe subconsciously comparing it to my LIttleAxe which is, after admittedly a lot of development, one of the best flying airplanes I've ever had. Same engine, same prop and fuel, same lines, about the same weight...but a world of difference in every way--speed, handling, handle "feel", takeoff/landing characteristics, etc.

To be perfectly fair, the FA does glide out and land beautifully, Bill said "floats nice", yes, touches down like a feather, once down it sticks down. Perhaps if I can get the speed worked out, other things will improve as well. I'm still messing with it! In fact I have in hand a borrowed AME .061 that I plan to try in it once it's loosened up enough. Some extra "grunt" may be all it needs. Although I still can't figure why the BigMig .061 works so well in the LA but labors like it does in the FA.

--Ray

Roger Vizioli · « **Reply #24 on:** July 23, 2007, 12:09:52 PM »

Ray,
Dont forget, AME needs pressure (bladder or crankcase)
Roger

minnesotamodeler · « **Reply #25 on:** July 23, 2007, 05:33:30 PM »

Roger, I'm aware...I can put an empty plastic tube where the tank is now, and run a bladder in it. I do already on my combat planes, even with BigMigs. Thanks for thinking of me though.

--Ray

minnesotamodeler · « **Reply #26 on:** July 28, 2007, 07:43:37 PM »

Just got back in from flying the FA--42' lines, APC 5.7x3 prop, tank cowl installed. Big difference! Got it down to about 4 sec. laps, still kinda slow (under 50 mph) but much, much better. I was running the numbers after last time out, turns out it was doing something less than 40 mph--no wonder it was struggling! With added speed, now it yaws out a little, guess I can move the leadouts back up where they were before.

Still susceptible to overcontrolling with the resulting slight stagger, but I think narrowing the line spacing at the handle will help that. It really needs a bigger bellcrank and less elevator movement. That huge flap back there makes it touchy, feels more like a combat ship than a stunter (well, except for speed).

Still, the handling is vastly improved. Stays up well in overheads. Bobbles on square corners (too much control). Doesn't have the deepest groove in the world but it can be held steady. I WOULD NOT move the CG back at all, plan location is just too far back. Remember mine is about 1" ahead of the plans.

And, it still lands beautifully. Last flight, it glided around to my patch of paving, touched softly down and rolled out so pretty...just makes a guy grin!

Next I will try the 5x3 3-blade that works so well on my LittleAxe, and if I can coax a little more speed out of it I may go back out to about 45' or so of line. With narrower handle spacing too, it should be tamed down considerably.

We're getting closer!

Oh, and the engine definitely appreciates being out in the slipstream...

--Ray

Roger Vizioli · « **Reply #27 on:** July 28, 2007, 09:14:18 PM »

Thanks Ray.
Keeping your notes, probably wont get back to building it until the fall.
The "other hobby" keeps me busy this time of year.
Roger

frank carlisle · « **Reply #28 on:** July 29, 2007, 06:28:21 AM »

That's a great report Ray. I'll be sure to use a larger bellcrank in mine.
It sounds like you're having fun with it.

minnesotamodeler · « **Reply #29 on:** July 29, 2007, 06:37:38 AM »

Roger, you mean you have to actually earn a living???

Frank, I'd use a 3" bellcrank with a pretty short pushrod arm. Don't need more than about 15 or 20 d. of movement. And balance it a little noseheavy according to the plans.

--Ray

frank carlisle · « **Reply #30 on:** July 29, 2007, 06:43:41 AM »

A 3" bellcrank it will be Ray. And on the nose heavy side.

Bill Smith · « **Reply #31 on:** July 29, 2007, 09:07:00 AM »

you may be able to tame it down a little by cutting one third off each end of the elevators and fixing them solid (AKA Trim Tabs)

I find the close spaced combat handle works for me but the really light weight of yours may be adding to the sensitivity.

minnesotamodeler · « **Reply #32 on:** July 29, 2007, 12:35:52 PM »

If you check the first picture in reply #14, Bill, you can just see the stationary ends of the flaps that I designed in from the beginning. May be that could be more extreme (more "tab", less elevator) to some advantage. The original 1/2A design by Ruschke or Netzeband or whoever was full-span elevator which I cut back. IIRC the original original--the "big" one--had the "trim tab" look and I preferred that so I followed it.

Closer-spaced handle I think will be an improvement, yes. Concerning weight, I hate to think an airplane can be TOO light! Although with that expanse of wing--something over 300 squares, about 320 I think--and 10.5 oz., I suppose the wingloading is ridiculously low. I wonder what a little ballast at the CG would do for it? Something to think about...

--Ray

Roger Vizioli · « **Reply #33 on:** July 29, 2007, 06:02:18 PM »

Quote from: minnesotamodeler on July 29, 2007, 06:37:38 AM

Roger, you mean you have to actually earn a living???

Ray, No! Been there, done that for 40 years!

Bill Smith · « **Reply #34 on:** August 01, 2007, 07:21:47 PM »

Sorry I missed the tabs. once you get the speed where you want it taping a little lead on it should be no problem and I know too lite is not something you ever think about normally but you are almost lite enuff to be rubber powered. LOL

Wayne Collier · « **Reply #35 on:** August 02, 2007, 02:22:29 AM »

"Concerning weight, I hate to think an airplane can be TOO light!"

Many full size sailplanes have water tanks in the wings just for the purpose of adding weight.

minnesotamodeler · « **Reply #36 on:** August 02, 2007, 08:39:17 AM »

Amazing...I can feel some experimenting coming up. Need a weight box on the CG!

--Ray

Bill Smith · « **Reply #37 on:** August 04, 2007, 09:12:48 AM »

just make it look like a belly mounted bomb.
Worry the competition. LOL
weight does not change the glide ratio too much (up to a point) but can increase the speed of the glide and the stability in the wind. But it does use a little more power.

Bill Smith · « **Reply #38 on:** August 12, 2007, 11:34:18 AM »

Had a bunch of family over yesterday so I drug out 5 of my 1/2 a planes for the kids to learn on and I took the smaller FA.
I had never flown th FA in this kind of heat and ended up cutting out the part of the cowl out between the air intake and the glow head. evidently there was just not quit enough air getting in there in this heat.
From the side it looks the same so I may just sand it out and paint it as is.
Note I took 3 kids with me to the local ball diamond and ended up with 8 and two dads and one cop (one of the neighbors miniature fake dogs had an attack, my fault). Cop got a good laugh and we were done by then anyway.