The manual states that it reccomends at least 65 oz in but you may be able to get away with the Hitec. Do you think you can make up for the difference in the control horns??? I am using the 3421 on mine which fits fine unless you are looking at moving the servo further up in the fin?, but in doing that is it possible that the chances of some fin flutter could be induced as you add weight further up the fin?


Chris

Chris,

I think that the Hitecs would work great given that they were flawless in the HotSpot. 65 inch ounces per rudder on that small model??? Seems like overkill to me. Just my .02.....

Kevin

Sounds good to me, I was just going by what the book said. I have to go a little overkill due to my lack of experience, but you guys are teaching me new stuff everyday!

Chris

I'm not saying that it's OK to go with less torque all of the time. You just have to use your head. Think about it.....What did we all do with our planes before all of these fine, high torque, fancy super servos/digital servos came along???? I was flying my 200 MPH Aggressor II with 70 inch ounce coreless servos on each elevator half!!! These were the "recommended" servos in their day. I had well over 300 flights on that plane/servos with no problems.

At least with a digital servo (such as the Hitec you have chosen) you will have full torque right off of center. An analogue servo may take as much as 15 degrees or so before full torque is had. See....You never had a full 65 inch ounces of torque right off of center anyway with the analogue.

Another thing....I'm usually a JR man but not when it comes to their thin wing mount servos. A buddy of mine has stripped several sets of these in his BobCat, both in the air and bumping the model getting it out of the truck. The gear train in these servos is very sorry to say the least. The Hitecs are all metal. I have held these servos in my hand and tried to move the servo with power on. It took a lot of force and left a dent in my thumb. Not very scientific but you get the point.

Kevin

Hi,

Use longer control horns if you're going to use a servo with less torque. I remember reading an article about that in MAN or RCM and it shocked me to see how much actual torque is acting on the surface when you use leverage like that.

That is, however, not always practical. In this case I will want a lot of deflection for knife edge flite. Tha Hitec do offer me the flexibility of programming them for up to 180 degrees of rotation instead of the more common 90.

Woketman,

Of course, you're right. I didn't mean to say, "use large control horns to achieve good leverage, even if it means you can't get enough throw..."

Within practical limits, of course. Not that you're going to need much deflection on the S'ray for knife-edge......

Does anyone know the kind of speeds this thing is capable of?

Chris

OK, I am convinced and will go with the skinny Hitec digitals. Thanks guys.

The fins are complete and I have started on the canopy.

the slot for the hatch latch. I will have more pics soon!

Chris

Here are some more pics of the canopy. The fit is ok but the sides hung out a bit.

I made these alignment pins out of aluminium to bring the sides of the canopy in. The seam still needs some work to conceal it better and will be accomplished closer the finishing.

A better fit

last one

Hey Chris!

Everything looks great! I'm guessing you machined yourself those aluminum pins? Any excuse to turn that lathe on right! I'm glad that you finally gave Emma some of the credit that she deserves. I agree w/the overkill, I'll just repeat the advice you gave me when I was building my Cap 232. "Why destroy a 2000$ model because you decided to save some guidas on one part?"

It's great to see the pics.. keep them coming! Talk to you soon, Joshua

I have about 25 flights on my Stringray and with a Ram 500 set to 145000 on rpm and it is doing about 180mph with no problem.
I have been following the posts on the StringRay and you all seam to have things in hand. But don't take my comment's on the stringray earlier about the speedbrake on the bottom,It is a must
you are all in for a rude awakening when it comes time to land this bird keeps on flying and flying and so on. It will stall around 15mph maybe. Keep a eye on your fuel and leave room for at least 2 go around. I can see some of you laughing about this post but you will see. Don't get me wrong I love the StringRay and I love the way it flys. The problem is it does not want to stop.
Here is my answer to the speedbrake problem and it works on mine.With them deployed I can get down in less then 250 feet.
every time. Good Luck and check six. Paul JPOFL

What gear and struts are you using?

Does the Stingray have any speedbrake designed into at all? Is your in addition to a top one?


Looks good for a P-70.....

Hi Matt. I am using the Robert 550 in this one but it was built before there was instructions. So the correct gear is the Yellow Aircraft or the Robert 530 the difference being the way the air cylinder goes. As far as the speed-brake on top it is not much use. I have found when deployed the Aircraft will drop off to the right. It is properly the hinge twisting. The problem on how to get it slow enough for landing is the thrust at a idle is enough to keep it flying. Someone wanting to use a turbine like the P80 or simular turbine would make this worse. Paul JPOFL

My are in primer right now. Waiting for the canopy before painting.
I have heard this stingray kept flying at idle. This is perfect for testing my thrust reversel gaget I was working on.

Tam

Guys,

Don't NOT install your speedbrake on top. Be careful about how you hinge it, make sure your angles and everything are right so that it doesn't want to twist one way rather than another. If every Stingray built has the same problem with the aircraft dropping off to the right when flown, then okay.

We're installing speedboards on all three gear, with a big one on the front. We'll get her slowed down.......

JPOFL,

Thank you very much for the insight and invaluable info!

Hummm i'm little concerned by now...I did install the speed brake as THE MANUAL said it, hinged as the manual, is it enough???...So did you test fly it before putting the kit out????

Can i have some clues about putting brakes on strut??? It's my first turbine kit so and i will fly it from 350' paved runway......

I hope I did not open a can of worms. Don't get I'm wrong I love the stringray and It flys even better. On the speedbrake on top maybe I would use metal hinges and operate the speedbrake with a aircylinder from the rear.I think the twisting is caused by the way the servo drives the speedbrake,with the nylon hinges.I have also used wingtanks to help slow up the plane and it helps.
I am building my second one and may make some changes.
Thanks Paul

Paul,

Can of worms? I don't think so. Please keep doing what you're doing, like all the info and notes (especially on any changes/mods you make and the results).

Glorfindel,

Uh...yes, sir, they test flew the model before they put it to market. Obviously, they didn't have roll issues with the speedbrake. That doesn't discount the experiences that others might be having, but since fewer than 5% of the Stingrays we've sold are in the air yet (it's a new kit), all the votes on speedbrake questions aren't in. So, just keep building. When you ask about brakes on the struts, do you mean speedbrakes? If so, I have a good idea of how I'm going to accomplish this. Email me.

Here's what I'd do for the strut speed brakes: the nose is a no brainer, simply put a partial door that opens in front of the strut as a big, "flat-to-the-airstream" panel. For the mains, fashion some flat panels that also attach to the struts and are retracted when the gear is up, yet big, out-in-the-stream panels when the gear is down. The only disadvantage that I can see is that your nose may not lock down if you are low on air, but just put a scrub strip up there and it'll be just fine.