Meesh

My Feedback: (135)

I weighed my Elan last night. Empty tank, 4 oz of Kerosene in the UAT, 22 lbs 9oz.

Add a Gallon of Kero to that and I'm looking at 29.5 lbs for take-off weight.

JetCat P70 for power.

Does this sound heavy?

No extra weight was added to balance.

Will maiden it tomorrow in Albany, NY

Bob

skywarrior

Hi.
here in Uk there are 5 liters to a gallon and that sounds like a lot of fuel to me. What turbine are you running?

My S/Sport in the post above is using the 2 1/2 lt tank from "Digitech man" in Holland and gives an 8 min flight with 250 cc when landed still there in the tank.

I dont know what mine weighs as it is not a standard colour scheme and I am not going to weigh it as it has flown fine but a gallon of fuel sounds a lot to man like me in UK where fuel seems to cost more than saffron !

Regards

David

Jet Lag

My Feedback: (26)

No,you will find the plane flys great and the P-70 is a perfect match.I have about 35 flights on mine now at 22 lbs w/o fuel and a P-70.

Meesh

My Feedback: (135)

Hi David,

1 Gallon in the US=3.8 liters.

I bought the 135 oz Jet Tech Kevlar tank. I'm running a P-70 so I probably won't fill it. It has two chambers in it, 100oz for fuel, 35 oz for smoke oil. I'm not running smoke now so I'll use the 35 oz side as my "Taxi Tank".


Bob

Meesh

My Feedback: (135)

Thanks Jet Lag. I wanted some reassurance that my weight wasn't excessive.

Bob

Big feet

LoL, I know the feeling, save up just to fill up, and thats just the planes.

john agnew

Finally managed to maiden my Elan yesterday, only one flight before the rain came on again!! It flew beautifully on the Wren Supersport with plenty of vertical performance and an excellent turn of speed at 19.5 lbs dry. I used about 5mm of crow to increase the washout mixed with flap and found that the Elan dived with the recommended down elevator mix. I elected to land without flap and made a perfect nose high touchdown with a 30 feet rollout on grass.

I have reduced the down elevator mix and will try her again today if the rain stays off! Well done Alan another superb flyer.

John

gooseF22

the down elevator of course depends on your CG but we used 4% which ended up being about 1-2 mm tops. mine is a little noseheavy. once you get it, its so transparent and smooth. I use a 2 second servo speed on the flaps, so everything is slow and smooth. when I drop the flaps, I throttle up a bit and its smooth. Took 3 sorties to get it right. its a wren SS too.

the jettech tank is 128 oz, split 90/38. 90oz gives the SS 6 min with about 1/3 tank remaining, so maybe three go arounds without hitting the UAT. dont know for sure, havent pushed it past 7 min yet.

Big feet

Hi Guys,
I had the second and third flight of my Elan today. The first flight was more of a shake down flight with only a couple of rolls, today she was given a bit more, knife edge flight, four point rolls, vertical climb, stall turn, and a few high speed low passes.
She flew them all effortlessly, with two gentle landings on half flap.
I think I will play a little with a knife edge mix and maybe some crow as well for landing, and see what happens.
Third flight I had the nerves almost under control, only one hand was shaking.

Everyone that sees this plane fly admires it, both it's looks, and how smooth it flies. You just gotta love it.

CPing

My Feedback: (2)

Today I had flights 3,4 and 5. All was good until I was looking everything over for flight 6...found both elevator covers melted. I remember someone having the same issue and it was suggested that the front of the turbine mount be shimmed. I did this during initial assembly but guess it's not enough. Setup is a P80 that's well centered thanks to a couple of washers under the front of the mount. Only other thing I can think of is a long taxi down wind and it was a bit windy today. I'll email Patricia and get new ones on the way but need to do something different so I don't melt another pair. Do I need to shim even more?

gooseF22

Thats when mine happened too, on the downwind taxi. When the wind blows up the tailpipe, it seems to act up. I am planning on spraying hi heat automotive paint on the servo covers to protect them from flash heat, just havent done it yet.

I think the servos need to be moved outboard a little more out of the line of fire. Or to the top of the stab? some guys coat them with aluminum tape too.

highhorse

My Feedback: (2)

Well, I've been wrong before (maybe once?) but my understanding of the term "hi-temp" as it applies to automotive uses (used a lot of it in my former engine-building days a million years ago) refers to the abuse the paint can withstand without essentially evaporating or peeling off of, say, an exhaust manifold. My understanding is that the term in this case does NOT imply any insulating properties whatsoever. In other words, if you apply automotive "hi-temp" paint to your servo covers you will still have melted covers. But at least they will still have paint on them!

Turbinac

I am working on this servo mount heat problem.

I have been in touch with the factory, who say the plastic used by the company that makes the servo mounts is the same one they have always used. We have used the same mounts for the last four years in literally thousands of Boomerang kits without a complaint, but now suddenly we see several similar cases. I can't be certain their information is 100% correct.

Though I have not had this problem myself, it's obvious that it is something that must be dealt with.

Our ambient daytime temperature in the UK is probably lower than in those places the reports are coming in from. That may help, but I am also very aware that a tailwind while taxying slow or standing at idle causes the heat to rise under the tail, so I always try to stand the model nose into wind when possible. I am sure the problem arises while the plane is on the ground, not during flight.

It has been suggested that a wooden mount may be the answer. I'm waiting for plywood samples to try them out.

You're right about the hi-temp auto paint. It is designed to stand the heat, not insulate against it.

BVM heatshield paint may be one answer. It is excellent, as we all know, for protecting anything from the heat. Colour paint can be sprayed over it, I think.

There's also a 1mm thick heatproof (like asbestos) sticky backed cloth with an aluminium top surface which is super effective. I'm also checking that out to see if it can be bought in moderate quantities.

Alan

CPing

My Feedback: (2)

Alan - Just my opinion but a melted cover seems to be the result of a combination of items rather than a design issue. Like you said, there are MANY Elans flying and only a couple of melted covers. My friends Elan has many more flights than mine and no issue, first day with mine and no issue at all. Only yesterday when the ambient temp was ~100F and long taxi with 10+ mph tail wind did I see this. Next time I'll be setting up camp at the North end of the runway

Guess I worded my post poorly, I just wanted to confirm the shim thickness that others have done. Here's my plan:
- Add another shim to the front of the turbine mount
- BVM Heat Shield on the covers then foil tape

skywarrior

Hi Alan,
Hows about in future batches moving the servo points away from the center. Obviously this is not possible on current production run but maybe a thought for the future.

Regards

David

Turbinac

I have considered it but it's a little more complicated than just moving the servos position. The thickness of the tailplane is less at the outer span so a change of the stab wing section used would be necessary to accommodate the servos. In any case, moving the servos outboard may not have the desired effect.
I believe the problem is always caused at low speed and so the heat spreads out under the tail area. I have also considered moving them into the fins, easiest option from the manufacturing point of view, but I don't like that idea for several reasons, such as field assembly, possible shift, etc.
Other suggestions such as moving the servos to the top surface of the tail are not being considered due to simple aesthetics.

Other ideas are popping up now and I am still on to it. I take on board all the ideas and suggestions.

Bear in mind this has happened to a very small number of these kits. It has not been a general problem, but I will get it fixed regardless. I may not post much until I have some solid answers, but I'll continue to watch these threads.

Alan

Kallem

I am now building an Elan and would be really grateful if you would post some pictures of turbine installations. I am fitting in the Simjet 3000 (should be same size as P-120) and it does not look like too easy. I remember reading from this thread that at least someone has done it. Where did you need to cut stuff away?

Thanks!

Kalle

Henk Visser

Hi Kalle,

I'am flying my Elan with a P-80 same size engine as the P-120 No big problem to fit inside the Elan!
Just take real care to center the engine right you won't have the servo cover melting issue

geh3

My Feedback: (84)

If you look in this thread earlier, there are plenty of turbine pics! I'm using an ARTES FALCON, goes like HL

gooseF22

Kalem
before you build, read this entire thread and you will save hours of little problems encountered. I think most everything is in here.

One thing. put the air tanks in first before you modify the tank mount. You will see if you read back. there are tons of large turbines in there. the model kind of is nose heavy in general, so mount stuff aft.

g

samo

What about putting a new Jet Central Rabbit in an Elan?

gooseF22

It would work, Im flying on a Wren super sport, which by the numbers is similar. It flies just fine on 18lb thrust. Since the super sport is so small and light, you have to put your equipment rearward....see my picture...Its the one with the red insides and the battery behind the tank.

Kallem

Hi guys,

Thanks for the answers. I have read the whole thread twice already, I am just lazy to go over it third time. Over 50 pages total... Anyway I just was hoping of getting some good ideas because the turbine mounts are too wide to push the turbine in. So you must have taken some wood or composite out to get it in?

Kalle

gooseF22

ya
dremmel it out. recommend you do that later in your install so you can balance. get the engine as far aft as you can but still leave 3/4 inch or so cooling around the outside. Its double ply, no problem at all

josecilurzo

Hi Alan,

our maiden flight with P-120 ( we changed the P70 to P120 ), was PERFECT, without any modifications on CG, absolutely the same flight conditions, but, the landing slope was a little faster, but, easily controlable with more incidence, the plane is perfect of 18 to 28 lb thrust!!!!!!

best regards

jose [sm=lol.gif]