Howard

My Feedback: (55)

ahicks,

Great feedback thank you sir. Why do you think folks have experienced flight control surfaces being ripped off or damage in the tail section I read that one gent had the aileron control horns (4-40) fail. Is there a story here or is it like a crash and then a specific brand of radio gets bashed? My sense is that if there is an issue it is a resonance vibration issue and not a control surface flutter issue but, I have nothing except opinion to support that. Also, what type of hinges would you recommend for the ailerons, elevator and rudder. Thanks.

Howard

Schummie

Redbiscuits,

What is the advantage of larger size versus larger pitch?

Regards,

Eric Schumacher, Netherlands

Schummie

I believe adressing the source of the vibrations is the best thing to do. I crashed my first one due to pilot error. I used the glow OS-160FX. I made sure that the wing sits very firm. I had no problems whatsoever whilst the engine has lots of power. I used the ca-hinges, with a narrow gap between the control surfaces and the wings. No closing of the gap with monocote or tape was used. No strengthening of the tail was used.
I'm building the present one alike. I just use slightly thicker rod (3mm).
You kan make a link of the chain stronger, but than another link will become the weakest point. You can read in earlier postings that most, if not all problems are due to vibrations. So I figure it's better to adress the source of the problems, and don't attack the symptoms. I must admitt howeverer that when using a gasser, there is much more vibrations than when using a glow engine. regarding the CA-hinges I use. When you pull out 5 well glued CA-hinges on a plane like this on a single airlon without flutter, then you really have a serious vibration problem. I further widened and cushioned the wing saddles to limit vibrations to the wings. Also it's important to have the wing on the fuselage without any play.

regards,

Eric Schumacher, Netherlands

redbiscuits

My Feedback: (6)

Hi Eric,
The pitch measurement of a prop indicates how far that propeller will move through the air per every single revolution of the engine. Simply going up in pitch will not slow the rpm of an engine, It will however make the plane travel faster. Not a good thing if you just want to relax on a Sunday afternoon.
A larger diameter prop reduces the engine's RPM at any given power setting, because there is more for the engine to turn over and hence more work to do. And slower turning props generate less noise as well, back to the relaxing Sunday afternoon thing.
I guess its personal preference what prop you choose to use. I generally stay with a 6 or 8 pitch on almost all my planes regardless of the diameter. I run a 11x4 on a Piper Cub that I have and it's one of my favorite planes because it fly's and handles so scale like.
Here is a thread on RCU on the OS 160 tach readings you might find interesting.

http://www.rcuniverse.com/forum/m_265238/tm.htm


Red.

ahicks

My Feedback: (2)

All else being equal, the advantage of the larger diameter prop over smaller w/more pitch is most easily noticed in the down lines and while trying to get the plane slowed down on short final. It will not build speed as easily and it will slow quicker when using the lower throttle settings. The larger diameter also has advantage in accelerating quicker.

The exact same airframe is flying perfectly after the control rods and clevises were replaced with much heavier components. The hinges were replaced with big Dubro pin types. 4 gallons of gasoline later, the before and after difference is pretty obvious in the fact there has been no further trouble (in spite of abuse in my case)? I agree that the failure source was not the hinges here. It was the mickey mouse hardware.

The gas powered are heavier, and throwing a lot more vibration (due to larger displacements?) into the planes - they seem to be the ones stressing the airframe. I wouldn't even consider flying without the tail bracing. Most gas powered need weight in back anyway, might just as well make what you can functional?

wesrcfreak

Would it be a problem if my engine ZG38 is not placed on the recommended 7,2834 inch (for glow engine) from the firewall?
My engine is mounted closer to the firewall. At about 6,6141 inch from the firewall.
Best regards.
Wes.

prr6100

When I installed my Zenoah G-38, I did not use the standoffs that were provided, I made some shorter, about 5/8" long out of 3/4" round hardwood dowel stock, if you had aluminum stock that would probably work also, this got the engine closer to the firewall and helped with the amount of lead in the tail, at the present time I have only about 5-6 oz of lead in the tail and I installed all the batteries, servos,etc where the instructions said in the fuse. I have replaced all the aileron linkages with carbon fiber and all the hinges with heavy duty giant scale pinned hinge types, I had severe problems with all these. We are planning on installing flying wires in the tail also.

ahicks

My Feedback: (2)

No, no problem at all! The closer to the plane's CG the motor is located, the lighter the plane should build?

wesrcfreak

Ok thanks guys.
Regards Wes.

Schummie

Maidened the sportster at last this weekend. I have the modified landing gear and a large tank (750 cc) to supply the thirsty OS 160. Even when totally fueled, the plane doesn't want to stand on its nose. At half throttle with no elevator input at all, she took off after 20 meters. Flying like a Caddilac. By that I mean easy, steady and not nervous. Flew a few rounds. Only one click of left airlon trim needed. Certainly the best maiden yet. Landing was easy, though she doesn't want too slow down. With the modified landing gear however, even at high landing speeds no tendancy to nose over. Then another run at max speed. With the OS 160 she's really hot plane. When in vertical rolling at high speed, the engine stopped. Luckily I was high enough. I put the nose down to get enough speed, and with trenbling knees, she didnt let me down. Landed at easy as the first time. I couldn't get the engine too start again. I decided it was enough for the day. After removing the wings, the problem was clear. The rubber bands were not srong enough to keep the heavy tank in its place at the high speed manouvres. The tank has slipped backwards during the vertical climb, and ripped of the fuel line. Now this engine as most engines stops when there is nothing too drink. This is corrected, and next weekend she's flying again. As I thought already, this engine doesn't vibrate as much as a gas engine. The CA hinges I used are all rock solid, as are the rods and control horns. Will keep you posted.

Regards,

Eric Schumacher, Netherlands.

redbiscuits

My Feedback: (6)

Congrats on your maiden! Have well over 50 flights on mine now and very good plane.
I have decided to put a 18x6 Xoar on it for this weekend just to see if it will slow it down a little. With and 18x8 it goes around like a warbird, not exactly how I like to fly.
Red.

Planejaw

My Feedback: (53)

Maidened mine last night. Fuji BT 34Ei. Took off beautifully, absolutely no trim needed over three full flights. On last flight, however, hit a goper-hole and the left gear/wheel pant bent back and punctured a hole in the left wing underside, which I repaired with CA and a Monokote patch. Will need a new set of wheel-pants now, but otherwise, excellent flying aircraft.

Very little right-rudder needed on takeoff, beautiful flyer. Absolutely smooth, even with a moderate crosswind blowing. Like most have said, she floats like crazy on landing. Have an Xoar 18-10, will go to an 18-8 or 18-6 to increase the drag factor just a little.

ahicks

My Feedback: (2)

Just thinking that if your engine is pulling the 18x10 OK, and you're looking to increase drag (on final and in your down lines), you might want to jump up to a 20x6? That's what I would do anyway. Next step, if necessary to get it slowed down on final, would be to start moving the CG back.... very effective!

Planejaw

My Feedback: (53)

Great idea Ahics. A little more drag from a larger diameter prop might just be the ticket. I also have the ailerons set up as flapperson (via the Spektrum DX-7), and that may help steepen the decent a little, but might also help her float a little further. Could almost use some speed-brakes, ala Mooney type aircraft, but much too complicated. Ordered the Stearman landing gear for it today, not going to take a chance on putting any more holes in the wing. Unfortunately, that will also serve to move the CG even further forward.

Full of fuel or empty, the CG is exactly at the forward most location, with landing gear at the stock location. Also running LiFe batteries (2 @ 2100 man) in the back of the fuselage, just above the trailing edge/wing bolt area, to help with the CG. May try to strap on a couple ounces of lead under the tail, as you recommend, to bring the CG back a little. Great ideas!!

Great to see another Michigan flyer out there!!

John

ahicks

My Feedback: (2)

Not sure how fond you are of those wheel pants, but you also have the option of running without them? That might eliminate the holes in the mono. for the time being. My stock gear have taken a terrible beating while figuring out how to get it to slow down on final. To the point of having to remove them to straighten in a vise several times. Never have broken the mounts in the wing though. But all that was while getting it sorted out. Now it floats in without issue. Guess I was thinking you might want to run without the pants until you get it dialed in some? The plane really doesn't need any more weight if it can be avoided?

Mine was flown today for the first time after switching the Quadra 42 out for the Syssa 30. Was able to eliminate the lead in the tail, eliminated the sub-c battery pack in the tail and went with a pair of AA 2000's now located just ahead of the wing. All this managed to drop about 2.5 lbs in weight. Motor still needs more tuning and maybe some experimenting with some different props (3rd and 4th tanks run through it today running an APC 18x6w). At about 14lbs, and with a little more power than the Quadra had, this is very different, much improved plane from what it's been. The acceleration and width of the speed envelope are much improved - remind me more of a nitro powered plane now.
FWIW, -Al

Kostas1

Very very nice pictures!

Do you know the AUW ?

Planejaw

My Feedback: (53)

After replacing the landing gear with the Super Stearman gear, noted that after the first takeoff two clicks of up-trim needed. Pre-flight also showed CG moved a little further forward, as expected. Will add a couple ounces of lead to the empennage prior to next flight.

Flew well on the first flight with new gear, but on second flight, at about 50' altitude into a pretty constant 8-10 kt wind, the Fuji 34 flamed out. Without much altitude, turned downwind and tried to make a very flat turn back into the wind for a landing on the runway. Landing was almost directly into the wind, but with low airspeed, didn't have much control and the landing was a little rough (surprised I even made it as good of a landing as I did, with little altitude and airspeed to work with!!). Bent one of the legs on the Stearman gear (boy, that's a strong aluminum gear), but later straightened it at home on a big vice. Slight damage to one wheel pant, but she's ready to fly again. Richened up the 34 by 1/8 turn. Having ambient air temps near 90 didn't help. Still getting used to the gas engines also, particularly in the warmer Michigan weather. Here are some photos with the new gear.

John

Schummie

Have repaired the tank wich came loose after the second maiden flight. It ripped the fuel line, causing the engine too stop. This will not happen again, or i'll eat the wing. made three 8 minutes flights without problems. Tracking like a train on rails. Nearly perfect rolls with the advised throws. I use 35% exponentional on the airlons, rudder and elevator. Engine still running rich on half throttle, making it run 4-stroking. Put in an "F" OS-plug in the 160 FX. This improved it a little, but not enough. Does start a lot better. Also a very thirsty engine. Even more than its boss. Next time I will set the mixture screw a little leaner, see what that brings. Further, the landing speeds are still too high. Due too the modified no problems like nose overs, but I like to come in slower. I now use a 18x11 prop, but maybe a larger one helps. Also I will bring the CG a little more to the tail. The ordered pilot may do the trick.
I'll include a picture. My proud son is holding the plane.

Regards,

Eric Schumacher, Netherlands

Planejaw

My Feedback: (53)

Great photo Eric!!

Like me, it appears you're working to get your ship dialed in. As I'm now running my first gassers (after years and years of nitro 2 and 4-strokes), there's some new stuff to learn here. Your landing gear looks very good, very nicely done!

This bird does track as if on rails. The long fuselage and generous tail surfaces have a lot to do with that. The Fuji 34 is adequate power for the flying I do. Just need to get it tuned well.

John

Schummie

Thank you John,

I've 10 years of buiding and flying under my belt. However this one is the first really big one. So I try to pick up hints and tips on this forum.
I've read about breaking airlons and elevators due to vibrations. I did use all the supplied hardware, exept I used 3mm rods, which is a more used size here in Europe. A glow engine doesn't vibrate as much as a gas engine. Till now nothing has come loose. The next flights I try and get the engine running better in the mid range. Turning the mixture screw 15 degrees every flight. Also I put the CG more aft in very little steps. Since I use a 750 CC tank just behind the fire wall, I try too prevent CG problems when the tank is nearly empty. Se exept from the modified carbon landing gear, everything was built straighforward. No pump, or in-flight glow drivers. I do use 2 lipo batteries of 2200 mah each. Also a voltage regulator to keep the voltage at 6V and thus not burning the servo's. Much can be said about how much power is enough. Personally I feel when running the OS 160 too its max, this plane becomes really hot. So I mostly fly it at half throttle. So yes, your Fuji 34 has enough power I think.

Regards,

Eric Schumacher, Netherlands

Planejaw

My Feedback: (53)

Great picture Eric.

Yes, the gas engines can really vibrate. I went with 3/16" carbon-fiber tubes with titanium rod ends (4/40), with the large dubro ball links. I check everything after each flight. I did lose a bolt from my ECU box that fell out after only one flight, was even lock-tited in, so installed a new one with locktite and some CA.

I'm running the new LiFe batts in all of my airplanes, just converting them over this Spring. They give a solid 6.6 volts with no need for a regulator on the receiver, but do need one for any of the ignition units (Fuji) which cannot support over 4.8 volts. The LiFe's hold their power over a long period of time, which is much better than the NiMh batts I've used over the past few years.

The Fuji still needs a lot of breaking in, even though I have about a half-gallon through her on the test stand this past winter. I've got a Fuji 32 (no longer made) on a Great Planes Giant Big Stik, which runs very well. Iv'e got a Fuji 43 in a Great Planes 25% Yak 54, which has little break-in time on it, so hoping me and my son get some good flying on it this summer. My H-9 1/4 scale cub has the Zenoah 20 in it, and it too is very new and needs some good quality break-in time. Too many planes to fly, so hoping for a nice warm summer with light winds and gentle rains...neither of which we've been blessed with so far this Spring.

I like your idea of moving the CG back in increments. I've got some GP stick-on lead weights (about 3.5 oz/strip) and I'll begin adding some to the empennage. I installed an 8/32 bolt/blind nut on each side of the fuselage at the forward-most CG location, then unscrew it and hold on to both bolts to let the fuselage teeter and see where she balances. Kind of an easy and quick way to know where you are, particularly if you like your CG to be somewhere near the forward location. I enjoy more sport/scale flying, so not into any extreme aerobatics, hence, rearward CG is not all that important. I'll get mine to balance with a little strip lead so she'll just tip back a little at the forward bolts. By the way, also put two bolts on either side of the rear-most CG, so also have that rear-most location covered. A little 1/8" ply for the blind-nuts to go into helps as well. I'll include a picture of the set-up that I have on a H-9 Pawnee, for reference.

Keep me posted, good to hear from you.

John from Portage Michigan

ahicks

My Feedback: (2)

Playing the part of devil's advocate here regarding small trim changes. How do you know you've gone far enough until you've gone too far?

FWIW, I'm a proponent of big changes - so they are easily recognized. Obviously made within reason of course! That may be just me though...

The "don't exceed" CG is 1" back. I'd suggest you try 1/2" back to see what you think. That should be far enough back to notice the difference easily - while maintaining the good manners you're both describing. I'm a little further than that yet, but have a season with the plane under my belt. Might be pushing it a little harder that a freshly maidened plane.

John - Warmer weather is going to use a little less fuel than cooler. I had to lean tweak both of mine Sunday.... -Al

Kostas1

Eric,


i am really jealows now

Very very nice Giant SS

Planejaw

My Feedback: (53)

Great observation Al. The idea of gradual change in the CG is a good way to go on this bird, and as you have said, you've got a season with her and you have had a chance to see how she behaves with changes to the CG. I think a little lead in the tail is in order!!

And yes, finding that the Fuji's needles do need a little tweaking with the warmer weather. Flying in 50-60 degrees is a little different than this past weekend when the temps were hitting near 90! I'm also looking at putting a breather nipple on the diaphragm side of the Walbro carb. Some posts have indicated that the disturbed airflow in a cowled installation can cause havoc. Worked on a GP 25% Yak last night with a Fuji 43, had the high and low needles at factory setting and everywhere else in-between. Great idle, great top end, but when moving the throttle quickly from idle to full, RPM's sagged and engine would quit unless you brought the stick right back to idle. Didn't seem like any adjustment, rich or lean on the high or low-speed needles would resolve this. Again, my first season with Gas and having a few teething pains here and there.

Thanks for your input.

John from Portage Michigan

wesrcfreak

Hello,
Yesterday I flew my super giant supersportster for the first time.
I made three short flights. I using a Zg 38 engine 20x8 wooden prop.
3mm titanium rods which I have made.
Toni clark heavy duty ballinks and heavy duty hinges.
Landinggear I made of aluminium 6060 T6.
I start with the CG on 139mm. fly perfectly without trim.
Only landings are a little bit fast.Maybe I put the CG a little bit more to the tail of the plane.I going to try the CG on 143mm for slow the plane down on landings.
Short movie soon on you tube.
Regards Wes.