RE: Fuel tank issue...
 

Thanks Kelly, Yes this is my first jet. I have build planes kits before. I just need to take my time. I was stressed out last night also. I think i'll be fine.

RE: Fuel tank issue...
 

I actually thought the instructions were pretty good. I did not change a lot.

I did hinge the elevons a little differently (put it in this thread http://www.rcuniverse.com/forum/m_76...hinging/tm.htm ). I also cut about 2 inches off of the fins, they looked a little tall for my taste. I made all of the surfaces removable with pins as well for painting ease.

I run the stock Yellow retracts with BVM struts, wheels and brakes. I run full gear doors (a sickness) as well. I bought the Robart gear to replace the yellow as they seemed a bit flimsy but they are OK after about 100 flights (maybe more).

There was talk about needing a second speed brake on the bottom or some such thing, I think the stock one is fine just make sure you have very good mechanical advantage on that speed brake linkage and run a fairly good servo (I run a 9411), in order to make sure it opens.

It is not an easy plane to fly, very small and fairly fast (180 to 200 mph, being small makes it look like it goes 300)

Photo courtesy of Uncle Joe.

RE: Fuel tank issue...
 

I agree with matt about the underside speed brake. The stock brake on top appears to be adequate from what I've seen. I run mine on a HS 645MG. The only changes I made were enlarging the sevo pockets in the wings, using larger (and more) hinges, and I changed the layout in the equipment tray area to get the CG right.

I had a bit of an issue with roll trim on mine, which may have simply been due to my choice in servos. It was tough to get it way out in a turn, since you couldn’t really trust it to behave as you’d expect in a turn... I’ve since installed a pair of way overkill HS 5945’s and the elevon hysteresis appears to be much less. Looking forward to getting it in the air again in a week or two.

Matt, any chance some of you guys can make the Whidbey Island meet? I know it’s a bit of a haul, but it sure would be nice to see more of the California crowd up in these parts. I hope there’s another stingray there this year, since recently Chris sold his. We flew them together (wide open for a bunch of it...) and his knees were shaking for the next 15 minutes! [sm=biggrin.gif]

Kelly

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Thanks guys. Great information! Are rudders required by AMA?

RE: Fuel tank issue...
 

Unless the rules recently changed, I believe they are required. Besides, on the stingray it's probably easier to proceed with rudders vs filling in the void in the fin. The only tricky part I found was getting the hing in place. Sliding the surface into place required flexing the hinges a fare bit.

Kelly

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Did you guys glass the wings and fins? How do you get the balsa wings so shiny with paint? glossy paint? And what kind of paint do you use? Thanks.

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I glassed with 0.75oz cloth and z-poxy. I sanded, re coated with a thin layer of resin, sanded again, primed and painted... Mine's done on the cheap with with rattle can spray paint. You don't need to glass the fins, just the wings, elevons, and rudders.

Kelly

RE: Fuel tank issue...
 

Great thanks!

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Did you guys use Y servos extions for the rudders and elevons? And also elevon mixing correct? And what about the sterring servo? Usually the rudder and sterring are connected. Not the case with the Stingray. What channel does the sterring servo go in?
Thanks!

RE: Fuel tank issue...
 

You can use a Y cable for the rudders but not the elevons, they need to be on seperate channels. Just what RX channel each elevon (left and right) plugs into is up to the specific radio and how it is programmed.

Yes it is elevon mixing. Elevator and Aileron function using only 2 channels on 2 surfaces. It is USUALLY mixed in the transmitter.

Do you mean are the steering and the rudder mechanically connected? Because that is pretty rare in the jets I have seen. On the other hand, the rudder and nosewheel steering servos can be ELECTRICALLY connected, but sometimes require a reversed servo as you cannot get the correct rotation given how the servos are mounted. I usually run mine this way, a reversed servo on the nosegear, "Y"'d to the rudder servo(s).

Well as I said if they are "Y"'d they are all on one channel, usually the rudder channel or channel 4. In my Stingray, I did things a little differently, I put each rudder and the nose wheel steering servo on a different channel. This lets me set the trim of the nosewheel with a knob, and also lets me cant the rudders inward together, acting like an additional speedbrake, works pretty well.

Hope that helps,

RE: Fuel tank issue...
 

Hi Kelly,

Sorry I missed this.

I have the SAME issue with roll trim, I cannot get it fixed. At first I though it was my thumbs but after 100 flights I know better. Of course chopping the tails off may have had something to do with it, who know, it flies well enough.

As for Whidbey I am not going but several of my frineds from Los Angeles are, it should be a pretty big turn out from down here.

Regards,

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How many batteries are you guys using for your receiver and servos? I have one 1500Mah Nimh. Should I get a bigger one with so many servos? like a 3000-4000Mah lipo?

RE: Fuel tank issue...
 

Don't sweat it Matt,

I've since flown mine a few times, as seen in JohnVH's Whidbey photo threads, and the roll trim is much better but just not bang on. I'm gonna give up on fixing it, since I don't think its a servo thing any longer. I'm pretty sure it was partly servos earlier, but they're pretty well bang on now. I've heard form a few skilled Aero guys that it may have something to do with having fins that are too large, while being too close and above the CG. If that's the case, yours may fly better than mine... Its basically the opposite of dutch roll, where over compensating with extra fin creates a spiral dive tendency...

I know it won't track nearly as well as my HotSpot, but at least its enjoyable to fly now so I'll leave it as is... I've only got 15 flight on mine so far, but I can see a day when I'll want more than the 14.5lb of thrust I have now though. I'm surprised you still haven't tried a P-70 on yours! I'm tempted to play around with a 600R one day and over rev it a bit for a couple extra pounds, then see what kind of speeds I can get out of her on a data logger.

Hey Moe, I only run a single 1500 mAh 4.8V pack, although I check it frequently and recharge often.

Kelly

RE: Fuel tank issue...
 

Thanks Kelly!

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No problem Moe, I would run a redundant battery setup in it, but there just wasn't any room left over. That, and I wouldn't want to screw up the CG... You can get this thing to balance on the money without any ballast lead, but you need to cram all the hardware as far back as possible. There was virtually no room left over for a 2nd pack...

Kelly

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What kind of spray paint r u guys useing? I just primered it with filler primer, now I am ready to paint it. (on the cheap) with spray paint. Lacquer or Acrylic enamel?

RE: Fuel tank issue...
 

If you guys are having roll trim problems on this style of airframe and the servo's have been ruled out you should take a real close look at the thrust line and whether it is off in the left to right direction. With the sweep angle any side thrust will cause a little yaw then a little roll and you can't just trim it out with the elevons.

RE: Fuel tank issue...
 

Hey Moe, I did mine on the cheap with Acrylic enamel. I used a base white with metallic red and gray tones from the local auto parts store. You can get good results, but make sure you use ‘3M Fine line’ masking tape. It’s a blue plastic tape which cost me around $18 Canadian for a 1/8” wide roll. It’s available at high-end auto parts stores.

Chris... Good suggestion, thanks. I’m pretty sure mine is close to bang-on but I’ll have another look at it.

Kelly

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On my robart struts I only have about 1/4 of an inch to move. How can I explain better? hmmm. With my stingray on the ground and when I push down on it there is NOT much spring action. It bottoms out. So when I land most likely I will bottom out How much room do you guys have? I had to cut the struts off sooooooooooo much to fit inside of the wheel wells of the jet there is barely any movement in the struts. Can there be ajusted?

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Just shorten the lower strut so it slides deeper into the upper strut. Eric

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OK My eyes are spinning now that I just finished reading this thread from start to finish.

I have a Stingray kit on the way. Should be here in 2 more painful days of waiting.
I am planning to shoot for super lite weight and use a MW44 Gold.

I know that this is not the best choice for a first jet but it was a case of opportunity presenting it's self.

RE: Fuel tank issue...
 

hey guys, i am wondering what are the best servos for this plane with wren 54? If you guys don't listing the necessary servos! Also, i currently have spring air retracts, 201 with struts, that i had originally planed on using with the A-4 but i decided to sell the A-4 and i am wondering if i can use these or is it better to order the ones at 140. and the bvm nose strut? Thanks
andrew

RE: Fuel tank issue...
 

There is no reason not to use your Springairs. You need to check the amount to be cut off your struts as you may find there is no springing left with some struts. The recommended Robart struts for the mains work perfectly and these will work with your Springairs.

For elevon servos simply use the best possible: high torque, metal geared and digital. Rudders mini metal geared digitals.

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When r they coming out with it again? Yellow Aircraft needs to make it an ARF.

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It is getting close to building season here in the north.
Maybe I will finish building my Stingray this winter.