flyallday

On my H9 D7 w/ Power 60 I'm using the Xoar 18x6 Axial prop with great results.


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That's a nice prop! Think I'll give it a go now that the LG has been repaired on mine.

Harry

flyallday

Thought I would share the fixed landing gear and new wheels. Ended up painting with house paint and sealing with Krystal Clear flat. The Williams are a tad heavier than the stock wheels and I may be able to remove a little lead.

Harry

Bob dunlop

My Feedback: (1)

Nice detail work om the wheels!

flyallday

Thanks Bob, now its time to take the shine off the rest. Was waiting until I got used to flying her to start to scale it out some.

Harry

Mustang Fever

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Been working on 'noopy when I feel like it, but things have changed- I've got the props and the Castle esc, and the motor and packs are on the way from HK, so I gotta get cracking, as I want it to fly at my Midland club's electric fly less than a month from now.

The new tail section is finished and RTC. As the stab saddle was intended for a symmetrical airfoil, I had to come up with a flat surface for the new Clark Y stab to mount on. I also wanted to make it removable, so I can put shims under it if required for the final trim. Solved both problems by "pouring" a new stab saddle out of a 50/50 mixture of epoxy and milled fiberglass. This not only resulted in a nice saddle, but I drilled and tapped it for four, 4-40 screws to hold it in place.

The elevators will be hinged with covering, right now they're stuck on with tape.

Mustang Fever

My Feedback: (2)

A shot of the poured stab saddle. The plastic dams I used on each side leaked a little. Hopefully I can peel off the very thin epoxy in those areas after it cures a little more. [:-]

pimmnz

So tell me why you are using a flat bottom (cambered) airfoil when the original used a symmetric 'foil? Since the stabiliser has to lift both ways, at different times through flight, surely a symmetric foil would be more efficient (and scale)?
Evan, WB #12.

Mustang Fever

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All of the multi wing WWI fighters I've had, including the Camel, try to go nose up at any speed over 20 mph. Probably due to all the lift from their flat bottom wings that are set at positive incidence. They can become almost unmanageable when turning into a strong headwind. I was able to correct this quite a bit on my BUSA DR-1 by putting in all the downthrust I could, and making the stab removable so I could shim the leading eddge to get positive incidence.

I thought on this mod I would try a lifting stab with very little positive incidence, along with more downthrust than originally provided. (Don't know how much I can get in there without making it look real dumb, so I'm relying mostly on the lifting stab.)

Scale is not a big issue with me- I go for "airshow" scale- shiny colors and good handling, no detailing beyond some insignia. If you're really a scale nut, you don't want to talk to me, I'll just ruin your day. There were a whole bunch of guys following my DR-1 build until they realized what it was going to look like, then they all got POd and signed out.

pimmnz

Yep, the real ones did the same. That's why the Camel had a pilot adjustable tailplane. Since you went to the trouble of removing the original, probably better to have just built a much lighter (laminated outline) tailplane, of the original section, and just set it at a more positive angle. That way you still alter the trim, and remove a bit of nose weight at the same time while retaining the scale section. Win-win situation. As the trim is speed sensitive, why not just use the straight and level speed as your normal cruise speed? 20 mph at 1/6 scale is 120 mph full size after all, and just about right for full speed. Even at 1/5 scale, it is still 100 mph full size, and just right for most Camels. That said, I do understand the extreme speed/trim sensitivity of these old things, something the new pilots of the accurate full size replicas are just finding out. You should see the amount of 'down' elevator held on, for example, the latest rotary powered Fokker EV/DVIII versions during 'S&L' flight at full power. So even flying with what appears to be a lot down trim on the elevator is still 'scale'. I really don't get the 'elevator must line up with the stabiliser or else something is wrong' thing at all. It simply means that you are exceeding the 'zero trim' speed of the aircraft. FWIW.
Evan, WB #12.

Mustang Fever

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Evan:

I read that Sopwith didn't include the pilot adjustable stab on the Camel, that it was discontinued after the Pup because the extra weight back there caused CG issues. ???

Regardless, I stayed away from a lot of positive incidence as I've been told it is possible to stall the stab. I'm hoping that as speed increases, the lift generated by the Clark Y will overcome the pitch up. Also, when I did the weight and balance calculations, I discovered that the 60 size electric power system will weigh about 4 oz more than the glow, not including the tank and fuel. It will all be right behind the fake rotary engine, without the weight of the tank/fuel behind the firewall, so the extra weight of the built up stab should be manageable. (I'll weigh the whole mess after I get it done and compare it to the factory setup.) I'm really hoping I can do away with that one pound block of lead in a box that's attached to the firewall.

As for top speed, 20 mph would just be too slow for the wind conditions here. 40 seems to be about right for the WWI birds. (When I owned a sailboat, I was always becalmed and forced to use the iron genoa. Go figure. Maybe I should by another and park it in the back yard.)

Thanks for the info on this subject. I didn't realize how badly this affected the replicas. The terrible Mustang crash in Reno was caused by the same thing- the P-51 doesn't have sufficient + stab incidence to prevent a very strong nose up force at the speeds they race them. The stress on the elevator trim tab caused it to fail, resulting in an instantaneous pitch up that caused the pilot to black out. The really sad part is that the identical failure occurred several years ago, and the our worthless Federal Aviation Admin did nothing. They should have grounded everyone of those aircraft, have the stabs torn down, and inspected for cracks in the tab area. That still hasn't happened, to my knowledge. Maybe some of the individual teams have done this, but nobody's talking about it.

Old airplanes have an endless bag of tricks that have to be guarded against- I worked on 20+ year old F-4s for 14 years, and issues were constantly popping up that the original owners never had to deal with. Not long after the Soviets shot down that KAL 747, one of the Air National Guard F-4s from New Jersey landed after a TU-95 intercept, minus an AIM 7 Sparrow, and the launcher hooks were hanging open like it had been fired. You wouldn't believe the panic in Washington that ensued until the NJ load crew pulled the cartridges out and found they had not been ignited. Turned out a part that was never a problem had developed metal fatigue, bent, and although the rack passed the "locked" check during loading, it opened up and dropped the missile in the Atlantic.

pimmnz

Know what you mean, I've ben involved with commercial aviation for many years, and the same thing happens, new bits break, new repairs keep on coming. To illustrate the point about the old ones, the image is of TVAL's Fokkers, you can see the 'S&L' attitude of the D-7 and D-8, and the amount of elevator held. No doubt the pilots would consider the airplanes 'tail heavy' but we modellers know that it is not the case, you couldn't fly it if it was, but they really did need some sort of pilot operated tail trim device...
Evan, WB #12.

Mustang Fever

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That's really dramatic. I thought I had a bunch of down trim on my DR-1, but it pales in comparison.

Did you get a chance to get down to the harbor when the Volvo ocean racers were there? The wife and I have been watching that on the telly, and have been impressed by the skill and courage of the crews. Planing hulls on the open ocean. Wow.

pimmnz

Yep, but not so much to see as it was pretty closely guarded. I am in awe of those guys, sailing a bit of plastic and then getting some pretty horrendous injuries, and having to just put up with it until you get to some land...and bounced the whole way.
So far as the trim you see, yeah, they need a pretty good push to keep them level, not something to be done for any length of time. The pilots have a bit of bunjee cord they can wrap around the stick for longer flights, to relieve the arm muscles. You can see how 'tail high' the D-8 flys, the D-7 seems to fly with the upper longeron along the line of flight. I will see if I can find a similar piccie of the Camel, just to see what it shows...
Evan, WB #12.

pimmnz

As promised...and some data for dirtying...
Evan, WB #12.

Mustang Fever

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#3889 is really holding some down elevator. I hope my lifting tail eliminates some of that, anyway.

Turns out my design for the elevator didn't leave enough room for good iron hinging, so I'm going to have to try CAs. It's storming here tomorrow, so I should have time to work on it.

I goofed off today, put the first two flights this season on the DR-1. The more I fly it the more I like, it's so weird, like flying a stack of dishes around. The only thing I use ailerons for is to level the wings during takeoff and landing- that airplane is a rudder bird. It will roll, but I have to be patient.

pimmnz

Again, just like the real thing. Almost any two/three winged airplane built before 1930 will be a rudder/elevator airplane. From what I have been able to gather, the DR1's ACM was being able to turn without banking. It's pretty unstable, directionally, and was able to give the following airplane no idea which way it was going to go...Well, it couldn't actually catch anything, and certainly couldn't run away...
Evan, WB #12.

tree2tree

I'm still enjoying the Camel now with about 80 flights. At the field the other evening, there was no wind - and no other guys either! The aircraft flies so slow and stable that I was able to pick up my camera with my right hand and shoot some pictures, while guiding the plane with rudder and throttle. Yes it climbs slightly with throttle but I am OK with that. There is no trick about the ground shot.

Mustang Fever

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Nice airborne pic. The Camel just looks cool, no argument.

I was just looking again at that shot of the replica, 3889, and realized what the designer did to get the CG right: the pilot and machine guns are shoved way forward. Looks like the guns are right behind the prop. That doesn't surprise me at all. I've read the original was considered tail heavy by the pilots. It looks like it has a real rotary engine, too. (?)

jasona

I'm jealous - I twatted mine! (See below) Got to finish my Spitfire first though before I can start repairs on the Camel.

flyallday

Bummer... they fly so nice unill you get on the ground. Easy to twatt.

Harry

jasona

I let it get too far away from me and it went out of range. It got off pretty lightly considering it was "free flight" for a while and went through some bushes and a tree!

flyallday

"If I had all the money I've spent on radio-controlled models, I'd spend it on radio-controlled models." Thats really good.

Harry

jasona

Ha ha! Thank you Harry!

flyallday

Just curious. what radio are you using?

Harry

jasona

Futaba FF6