TomCrump

It's not a race. Slow down and enjoy what you are doing.

acdii

Cracked up my P-51 last night with a dumb thumb move. For some reason, not a lot of rudder when landing and I couldn't get it to crab in for landing, north wind was pushing it south, and attempted a go around, and needed to avoid getting too close to a tree, so throttled up and I guess too much elevator and flaps still retracting with the gear still down culminated in a snap over and a very smooth loop, right into the ground. 2 more feet in altitude and it would have cleared too.

So the Cub gets pushed back a bit to repair the Stang. Snapped the fuse in half and ripped the gear out, damaged 3 or 4 servos in the process too, so have to get gear sets for them.

I flew the LT-40 first and had a blast with it, getting really good at landing from my bad side, which is right to left or clockwise, where its opposite control from what you look at, and can grease in landings now with near pin point accuracy. Greased it in at high speed and touched down right in front of me no more than 10' in front of me too. I then found the top hinge had snapped on the rudder, so had to cut it off and rehinge it last night, but its ready to go again. I also got the OS 52 singing smoothly too, I leaned it out a bit and now no more burble, and it books across the sky.

FlyerInOKC

My Feedback: (6)

Sounds like a nice opportunity for a rebuild thread in Crash & Rebuild! Don't forget the pictures!

skylark-flier

OW! Sorry to hear about the "body by collision". Doesn't sound like it's terminal though - she'll be back in the air soon enough.

Yeah, Kadets ALWAYS make a day go smoother. Ain't it great???!

TomCrump

What do you guys think about the Rascal 72 ARF ?

Would a Himax HC3528-0800 be enough power ?

MartyPetriSr

Well here it is after 3.5 days of work. I covered it with sticker paper, what a mistake that was. The stuff doesn't stick well, had to use spray adhesive on the foam and the sticker and then where it goes around curved surfaces, had to slit and use POR and it is still lifting in places. Won't use that again. The weight gain wasn't so bad, but the finished article is less than what I had hoped for.

Marty

FlyerInOKC

My Feedback: (6)

Looks good from the photos!

acdii

http://www.rcuniverse.com/forum/cras...l#post11843252

Going to start the rebuild either tonight or tomorrow. I already stripped the covering and examined the damage, looks like it wont take much in extra material, just covering and a few small pieces of skin for the wing and gear blocks. The hardest part will be joining the fuse back together, since it splintered the fairing, and has to be squeezed back in place so everything lines up again. Once I get that done I can soak it with thin CA, and glue the formers back in place. May need to put some scabs inside to bridge the cracks, but not much different than when I cracked my LT-40 in half. Seems like all my big crashes except the 4* wound up cracking the fuse in half with little damage to the wings, I tend to crash them wings level.

Funny part was the pilot had broke loose before I flew it, so he was bouncing around the cockpit all during the flight, no wonder it crashed, drunk behind the stick.

FlyerInOKC

My Feedback: (6)

Those drunk pilots will do it every time!

acdii

You should see the pilot my friend has for his Cub that he put into a gravel pit and then later through a tree. Same pilot from both, I swear it has a complete look of fear on it.

MartyPetriSr

I have started a build thread on that other site, so if you are interested to build this model, please refer to that thread, it has all the latest info.

50% Kadet Sportster Foamie

Thanks,
Marty

acdii

Well my Mustang will survive and fly again soon. Damage wasn't too bad to either the wing or fuse, and a few hours of work will have the structure all back to normal. Only one rib got demolished so will have to dig through my kit scraps to locate the correct rib outline and make a new part from the spar forward. New gear rails on both wings and some sheeting and its ready to recover and fly. Fuse just needs some patch work on the sides and reinforcing where it cracked, recovering and its ready to fly. Now to find the servo gears that got stripped.

acdii

Oh and here is a tip for all you fliers who run gas. Make sure you take the glove off after starting the motor and before you take off. I forgot to take off my glove after starting the DLE 20 on my 4*120 and took off and couldnt understand why the plane was so squirrley, then realized I still had the glove one. It made for a very entertaining(for the bystanders) flight, thankfully I was able to land it OK and take the glove off, then took off again and she flew Great! What a blast this thing is, and verticals are nearly endless, It does eventually peter out, but at a height were the plane gets ReALLY small. I also did a few hammer heads and tail slides with it. Still need to work on my landings though, Then again I was flying with the wind behind my back and never landed a plane comeing almost right at me, and wasn't sure where it was in relation to the edge of the field, so it hit hard enough to hit the prop on the third landing, but the first two landings, even with a glove on were nice. The wind just kicked up a bit more on the final flight.

So my landing issues with the plane going too fast and just floating are OVER, thanks to Bob! That 16X6 APC prop is working out great on the DLE 20, In fact one of the guys at the field said he has never seen a 4*120 move that good.

SushiHunter

My Kougar took a rather hard landing this past Saturday but apparently it will also survive. I came close to just ordering another Kougar kit and stripping this air frame down of all parts that are good and reusable. But after getting it home and going over everything inside and out, I think it's going to be ok. I actually got it all repaired within a few hours on Sunday (yesterday). The Kougar is a 40 sized a/c but ever since the first Kougar I've built and flown, I've always put in .61's and ran stock exhaust, and recently .65AX with a Mac's tuned pipe system in my newest Kougar. I've only flown her on the pipe a few times for just a few moments at a time because it's really a hand full at that throttle. I usually keep her right at about 50% throttle. She's got telemetry sensors and I'm using the FASST system so I'm seeing 92mph on the display at 50% throttle.

I think my issue is, I may not have completely built her up to handle that type of speed, pressure, power, etc. The one and only flight for this specific day (Saturday) kicked off well. I discovered from previous flights that I had to adjust the length of the nose wheel assembly due to the fact that the plane had a very slight nose-up stance and would lift off prematurely while on it's roll-out. I was able to get her up but was right about at the threshold to having a wing stall. So I removed the slight nose-up stance and the plane had a really nice roll-out last Saturday. I was flying her like I stole her and she was performing awesome. However, about six minutes into the expected eight minute flight, I lost roughly 95% of the up elevator ability. The minutes leading up to this issue, I had her doing high speed passes roughly 75 to 100 feet off the ground and I'd put her nose up to about 300 feet, do a 180 roll and then have the plane do an inside loop and head downward while pulling it up with roughly 75 feet of alt when she levels out. She flew like a dream, and this is also why I really wanted to save her instead of my initial idea of stripping her down and starting with a new Kougar build.

So at about the six minute mark into this flight, I started noticing that she was not that responsive when pulling up on the elevator stick. I knew something was not right so I got her into a final approach pattern. I throttled back a little and she lost alt very fast, even though I was pulling up on the elevator stick. If I gave her half throttle she'd start gaining alt but the speed was too much to try and land. So my final decision was made where I got up some good speed and some alt and then cut the throttle and turned her back towards the runway in a final approach pattern. She lost incredible alt in very little time when I cut the throttle. I hit the throttle once more during the final approach where she just maintained her current alt but again gaining tons of airspeed. I cut the throttle for the last time and tried to glide her into the tall grass at the end of the runway. She lost so much alt, I'm sure if I had set her down on the paved runway she'd a been a loss. Instead I hit the tall grass which most likely really broke a lot of the speed and fall. Only one blade on the prop was sheared completely off at the spinner which leads me to believe the forward motion of the plane caused it and not the engine spinning. I've got a plastic spinner on her and that didn't get damaged in the landing. The clunk in the tank got thrown through the vent plumbing loop so It wouldn't move freely. There was a crack in the cowling near the spinner. And the last bit was a stress crack in the very center top of the wing running along the seam where both wing halves are glued together.That was all the damage I was able to see from the outside of the plane up on inspecting her once I got it back to the table at the club.

After removing the wing from the fuse, I inspected the internal structure of the bird. The cause of this crash was the elevator servo lost three of the four wood screws holding it to the hardwood cross beams. The servo is held into place from forward to aft. The two servo screws aft were both missing, but the hardwood support beam was still attached at both the starboard and port sides of the fuse. The one screw left holding the servo in place was located forward of the servo, however, the hardwood support beam had broke free on the starboard side of where it had been glued to the inside sides of the fuse. So basically the way that the servo was still attached, I could only get about 5% elevator action, since the servo was connected forward with one wood screw to a hardwood support beam that had broken free on one end and no wood screws holding it in place towards the aft. Basically the servo had so much play, sort of like a vehicle transmission with a seriously bad/broken transmission mount. It's apparent that at the speeds I fly my Kougar, the air pressure creates a tremendous downward force against the top side of the elevator when pulling up on the stick, which in turn creates an enormous amount of stress at the aft portion of the servo, where the two screws hold the servo to the hard wood support beam. These wood screws were completely pulled out and the front hard wood support beam then broke free on one side. Inspection of the elevator revealed absolutely no damage to the control surface outside the plane. So I'm convinced that the missing screws and the hard wood support beam was the results of the in flight stress.

With this type of speed, power, pressure, etc. this is the type of structural integrity jet guys prepare for when building and maintaining their jets.

Lessons learned for sure, in the area of construction. Wondering if I should now use screws to secure the hard wood support beams to the sides of the fuse instead of just gluing them in place. Wondering if I should now use machine bolts and nuts to hold the servos to the hard wood support beams. Also wondering if I were to position the servo a different direction that this issue may have not occurred. After getting her home and thoroughly inspecting her inside and out, getting the clunk back to where it needed to be, mending the hairline fracture in the top of the wing and remonokoting that area, putting on a new prop on and mending the crack in the plastic cowling, reconnecting the hard wood support beam with a bit more strength, and picking up some machine bolts and matching washers and nuts after work today from the local hobby shop. I think she's going to fly again.

Either way it was a really good lessons learned and if I do build another Kougar I'm sure I will incorporate a lot of this lessons learned into the new build. I'm just lucky no one was hurt, no property got damaged, and I didn't lose the entire aircraft.

skylark-flier

Geez, you came out rather lucky here - - glad the plane (and your nerves) made it. Yeah, you're right - lessons learned, for sure. With the speeds your Kougar is getting, I'm thinking that I would AT LEAST put a frame around the hardwood support beams - something like a tongue & groove joint. That would give you the added strength to the support beams that you probably need. I would also think seriously of using a "capture" system for mounting the servo to the beams. That way you can use larger screws than the holes in the servos allow, which would probably give you more secure mounting of the servo. Just a thought.

FlyerInOKC

My Feedback: (6)

92 mph @ 50%, I can just imagine what the top speed must be! Sound more like a rocket plane! I agree with Dave I would put a frame around the beams to spread out the glue surface. You may wish to consider look at a few other key areas to beef up just as precaution when you start to open her up.

SushiHunter

Thanks guys for the suggestions. Good timing too because I'm getting ready to start installing all the electronics into the SIG Komet that I finished building a few months ago. I'm planning to put the same make/model of power plant and exhaust into the Komet. I would have been pretty sad to lose the Komet due to the same issue I had with the Kouger last weekend. So far my Kougar is living up to it's name, cause I've had a couple of close calls over the past several months of flying it. It's definitely a cat that has nine lives and it's at about on number three right now.

Looks like I want to try the frame around the beams where they meet the bulkheads suggestion. Plus I'm also thinking of how to mount the servos onto those beams. The four narrow screws don't seem to be big enough. Thinking of trying machine bolts with washers and nuts. Good stuff!

My Kougar that I almost lost last Saturday.


My Komet that I'm getting ready to install all the electronics and Mac's tuned pipe exhaust system in. I don't want to lose this bird!

skylark-flier

I've kinda been thinking about mounting of the servos too - and my thought is that any kind of screw through the normal servo mount hole simply isn't going to be strong enough WITHIN the wood. Not much of a fan of the nut&bolt solution though. How about doing it like some of the ARFs that I've seen do it - pins holding the servo in the proper position, using the normal servo mounting holes, and a covering plate that will cross over the servo mount from side to side - and using larger screws than would normally be allowed because of the hole sizes, screw the plate to the beam farther out.

Geez, not sure that came out right, but the idea is to trap the servo with the plate, and screw it to the beam outside the normal width of the servo, using heavier screws.

FlyerInOKC

My Feedback: (6)

Hey Dave didn't I see a plastic servo tray made years ago that held the servos like that? Anymore old dinosaurs around that can remember that far back?

SushiHunter

If I remember correctly, the Kougar kit came with nylon linkage components. I went ahead and purchased higher quality Du-Bro ball linkage components (pictured below) instead of using the ones provided in the kit.

That could have turned out to be a really good call because I think the nylon linkage components provided in the kit would been used instead, they would have failed instead of the servo working loose, which had the nylon linkage at the control horn on the elevator failed, the plane would have nosed into the ground I'm sure. At least with the servo still attached, I was able to get a little alt control while power was applied.

skylark-flier

AHA!! Another dinosaur speaks up!!!! Hey man, pay attention to the signature - - "Old-school" MEANS "OLD-SCHOOL"!!!!! Oh, yeah - I have 5 planes still using those trays, as I type this. Two have their original iron-piston Fox engines driving them. Also have 2 more of those trays in a drawer at the moment.

Besides, there's nothin' wrong with old!!! "OLD" is what the Chinese took over, and made "cheap". Sometimes so "cheap" it works one-time only. I've had those items on occasion.

(and, "old-school" also explains why my 40 yr old Sr. Falcon, 45 yr old Skylarks (C/L planes) and C/L King Cobra are still flying).

acdii

Futaba radios used to come with a 3 servo tray that held the servos down exactly as described. I still have one or two laying around somewhere. This was back in the AM days.

SushiHunter

After retrieving the plane after I had landed it in the tall grass and, I got to wondering had this bird been an ARF if it would have been built strong enough to have survived what it just went through. I seriously had my doubts that it would have held up as well had it been a mass produced ARF vs being personally built.

FlyerInOKC

My Feedback: (6)

You got that right SushiHunter! ARFs are built by the lowest builder in some cases using hot glue for assembly, driving their employees to work as fast as possible, and with as little material as possible and still get the contract. I don't have to tell you the building philosophy of most kit/scratch/plans builders.

acdii

Yep, compared to the kit built planes that I had/have an identical ARF to, the build and materials are quite different. The P-51 ARF that I have it a lot lighter in build and easily snapped in half when it went it. The one I am building from the kit would probably not have cracked in half like it did, though the wing may have suffered more damage that what the ARF did. The ARF wing is built pretty tight. The other ARF's I have are pretty flimsy, in fact I was given a H9 Funtana90 that I would never fly, it looks like it would blow apart the first time I did a snap roll with it.

When I first got the SIG 4*120 the build quality looked really good, but looks are deceiving, when you cant see into the wing to determine if the spars will hold up to the abuse the plane is designed for, and after a few flights the wing blows off the plane, well, needless to say it wasn't that well built. Probably the reason why they no longer sold that one as an ARF.

The Biggest thing about an ARF is the warranty, the companies that stand behind the warranty are the ones you want to purchase them from. I was Extremely pleased with SIG for replacing the 4* ARF with a kit. I didn't mind building one from a kit, in fact I prefer it to an ARF, and it is one tough plane. The Thing that is good about an ARF is if you can get one that is identical to a kit in flight characteristics, its a lot less expensive when you are learning to fly it(Warbirds) than wrecking the kit you spent countless time and money on.

Speaking of ARF, by the time I get the T-Clips I will have forgotten I bought one, and will be surprised to find it at my door, like an unexpected gift. I am so hoping the build quality is as good as the prototype.