2K,

Those tanks look like they could be moved apart a bit because there's some decent clearance at the top... Try offsetting them and rotating the brass tubes to the outside.

The Kevlar tanks that Starto' and I both used are so tight that they were practically laid up inside a Stingray fuse to maximize the fuel capacity. The Jet Tech tanks need to have the fittings rotated such that the brass tubes are turned to the outside. Then they only need a small relief cut in each side of the lower servo tray to fit it all in and clear the fittings.

How are the plastic tanks mounted? Are they fastened down to some sort of structure or left to be supported by the lower skin?

Also of note, I mounted the speedbrake servo on the opposite side of its mounting flange, from underneath. I used an HS-645MG and an HS-225MG for steering. They JUST fit! I think the 645 gave me some clearance issues, can't remember now.

Kelly

I second Kellys suggestion, you can see how tight the fit is in our birds in post 185. I too moved my speedbrake servo to the underside of the mount, the linkage is more ideal in that location.

Chris

Okay guys....almost done now! I'm going to finish up the details tomorrow morning and then send her off to be painted. I flipped the steering servo upside down to help alleviate some of the crowding AND because it was reversed from the rudders. Will keep you posted on the construction, or you can just visit my website: www.kcmoore.net/myfleet/stingray.html

Hi guys,


So for these 1.5 pound turbines, I assume from reading this thread you want to get the weight towards the rear of the plane? Will the recommended equipment installation yield a nose heavy model?

Also, I was planning to put the antenna in the wing, but I noticed it has carbon in at least some of it....does anyone know the layout of the carbon unser the balsa skin?


THanks in advance

Matt,

Can't remember if the manual specifically says where to put the internals, but hey most of us usually take the 'Tim the tool-man' approach long before that part anyway... To answer your question, yes I had to locate the internals as far back as possible to get the CG correct without adding lead anywhere. Try to bias the lightweight items (retract/brake tanks, etc) to the nose and the heavier items to the rear of the cavity.

As for the carbon, I suspect its full coverage inside the wing, laminated inside the top/bottom skins, because every cut I made in it ran through the carbon. You'll probably see it at the wingtip, wing root, and Aileron slot, and servo cutout... I thought about running the antenna out the wing, but changed my mind because of the carbon. Unfortunately, the big whip I installed looks a bit out of place but I figured it would give best reception. In the air its barely visible, but I might try a Deans ant some time later on.

Later'
Kelly W

PST Jets
North American Tech Support

Well my stingray has flown, three times in fact now. It wasnt without hitches, through no fault of the plane.
the first flight was wheels down as an air line unfortuneatly popped off the nose, so we lost pressure for the wheels. theyre spring air so they stayed down. It certainly didnt seem too much of a handful at that speed.

The approach was long and fast, I do have video, but its not that impressive compared to the other vids of stingrays. But it does show the approach speed of astingray without a speed brake.

After repairing the bent u/c legs from the overrun, it flew a second time.

This time id put 3/16 diameter legs on. Unfortuneatly i had to have the u/c block drilled to accept the thicker leg. Not deep enough as the flat id filed was at thetop of the leg. The leg came out in the air, damgled for a while then fell off. wheels up landing resulted into the long grass. No damage fortuneatly.

Third flight, front wheel didnt come up but flew okay for me as its only the second time i had my hands on the sticks of a jet. We had 21mm up elevator and 13mm aileron. The test pilot felt this wasnt enough so went to max rate on his box. I could have done with less exponential.
About 5 mins in it flamed out going upwind, so the test pilot took control and brought it around for a landing . Fortuneatly no damage. it turned out later we found fuel on the outside of one of the elec fuel valve for the autostart. I tightened the festo screws as they were slightly loose, so i think weve found the cause of the flameout.

The gas valve also wasnt as tight as it could be so i tightened that. Interestingly id recently had problems with starting due to weak gas messages, iw would light, get to 17000rpm, go to fuel ramp and then flame out. I was using increasingly more turns on my gas cylinder to get ignition. Tightening the festo connection solved this problem and i had five trouble free starts the following day.

im about to try and post some images, theyre 225k so im not sure if theyll post.
Ah the images are bitmap, ill try to convert to gif or jpg

Ill try again

Ill try again

how much does this plane end up costing?

You will be around $4000-$5000, I built mine two years ago and never really added it all up, did not want to know! E-mail me if you have any more questions.

Chris

how long of a flight can you have with these stingrays?

I fly mine for 7 minutes and land with about one tank about 1/4 to 1/3 full depending how aggressive I was on the throttle, it does not take much to haul some serious butt either!!!

Chris

Yeah...with a RAM500 and the stock tanks, we burn 64 ounces of fuel in about 5 minutes at full throttle (is there any other way to fly?) The Ram500 hauls the Stingray around quite nicely, especially if you pull up the gear. I'm about to order another one for a Winter project so I can take my time and re-engineer some things.

Here's a link to the video I made of Kyle and I flying them in formation...too much fun!

http://www.kcmoore.net/myfleet/stingrays_final2.wmv

VERY COOL VIDEO GUYS!!!!! [sm=lol.gif] There is nothing cooler than one of those turbines screaming by at FULL throttle. Chris, you've got to get your bird back in the air!

Brett

Hey Chris,

You coming to Whidbey? If so bring your stingray and we'll rip it up together. Hope you can make it! [8D]

I've got 10 flights on mine now, the last of which was just a couple weeks back at a local grass strip. With the same tanks (Jet Tech) as Chris and the same engine (J600R). I also fly for ~7 min and land with the 2nd tank 1/3rd full or so.

I hoped to have more air time in the plane by now but the availability of our local strip this year didn't work out with weather or other commitments. I'm still fighting with a bit of a roll instability which a local aerodynamics expert described as a spiral dive tendency. I just can't quite get the roll trim to centre. Its not an elevon servo issue since the elevator trip seems to be bang on.

Kelly

I know Brett, it is ready, just waiting on the fuel pump. I don't think it is going to make it for Whidbey though, what a bummer.

Chris

Hey Kelly, I am going to try my damndest to get my Stingray over there,I will be there either way. I don't have a fuel pump, it is the only thing left to install. I am hoping that it makes it here before Thursday. My plane has 41 flights on it now, I had a really bad landing that broke all the gear formers and main wing carrythrough former so I had to gut the entire plane. I redrew all the formers in CAD and Lasercut all new formers and repainted her fuse. Dean had mentioned your planes symptoms when he was down and we were flying mine, mine never really had any bad habits, the only thing that I know is different is my rudder servos are mounted up in box half way up the fin, this really stiffened the verticals up a lot but who knows if that is an issue with yours, the other thing that I noticed with mine is that it almost has a little anhedral in the wings.

If my plane makes it we are definately going to have to put on a show, that is if I have the balls!

Chris

Chris, if that's your only hold-up, bring it anyway... I'll have a spare FW pump in my tool box for you but you'll have to wait till I get there Saturday morning.

My jet's issues aren't really that bad, just not optimal. You just have to keep on top of it a little more than most, but its still easily controllable and safe to fly...

I don't think it has anything to do with the rudder control mechanism as the stock setup is actually rather stiff. It looks less than optimal, but it works quite well. I'm going to try sealing up the gear wells since mine also makes a distinct moaning sound when the gear is up. I'm thinking there may be some sort of turbulence generated on the underside around the gear, although I'm really guessing at that. The moaning could also be a result of the hole my nose strut made in the aft fuse area when it parted company on the 1st landing. Having heard of one or two with similar flight characteristics and a lot that fly perfectly well, I'm sure its something simple I know about already or have yet to discover in a few flights.

Kelly

Thanks Kelly,

I should have my other 600R here by then but please bring the pump just in case the engine does not make it. I am getting really excited, we are going to have a blast! I will arrive thursday afternoon so the Stingray should have a trim flight on it by then and be ready for some formation.

Chris

Hey all. I ordered the Stingray yesterday with all Yellowaircraft retracts and brakes. It will come with the wire retract not struts. Is Yellow aircraft's good? I see all of you have struts.
thanks,
Moe142

Anyone? Thanks.

The gear that comes with the kit is OK, but not as good as the Robart equivalent in my opinion. The nose gear side plates are prone to bending since their isn't a great deal of material above the trunion drive pin when in the extended position. I'm not sure on the material spec used, but I know the Robarts are made out of 7075, which has a sizable increase in strength over the far more common 6061 alternative. I do like the set screw end stops to adjust the end play out of the system, but I think a little more work could have gone into design for durability. The down side to the Robart is that the gear is slightly heavier and the nose strut will be shorter... A Robart 541RS ($78US retail) will be a direct swap out for the nose retract, only needing a slight adjustment in strut length to work.

Just make every landing right on the money and you shouldn't need to worry about that though!

Kelly

Great thanks!

I just got the stingray and have NO idea where to start. Do I need to keep the strofoam that the wings come with? What do I cut? I am ****IN lost! The instructions are not really that clear. Do I cut the wings so they look like elevons???? I might have to send this back.....

hate to say it but you may just need to take a deep breath and start with step 1 in the instructions... There are plenty of guys here willing to help you through it.

On the elevons. You need to separate them from the wing at the pre-cut slots, then bond in hard balsa strips for the hinges as I remember. (although it was a few years ago) Its not that difficult, but it is time consuming... You could save a little time in the elevons by building the hinges with a simple chambered hinge line rather than the radius with concentric hinges.

By your reply, is this your first jet? The Stingray is a handful for a first jet, although it may be alright for you if you're comfortable with a small plane going very fast in relation to its size... The energy management on landing is critical too.

Kelly