Scorpion from AD-Jets
 

Hi
I´m starting new tread for this popular plane , I hope it will help someone to decide how a what to build.
I have been reading about the Scorpion for a while now and decided to test one after recommendation from a customer.
I use Hawk Turbine and after this summer is mi Hawk 190R free for other missions :o((. So mi goal is to put a 20kg thrust turbine it the Scorpion.

After unpacking I can tel that the internal is reinforced and remade to the better but the outside is not much to brag about , lots of pinholes and small damages the is annoying when you are building, so if you can take that , don´t buy. A new paint job would fix it.
The weight of the airframe is 5kg , estimated empty weight is 11-12kg. Ready to fly 15-16kg. This bird needs more than 12kg recommended thrust in order to come alive, and most people are using around 16kg turbines. I will put a Hawk inside , that will give me 20kg Thrust and 10-12 min flight time on 3 liter of fuel. Will put in everything that is used in jets today as lights and smoke.
http://www.jetsweden.se/forum/e107_f...0_dscn3790.jpg

RE: Scorpion from AD-Jets
 

Hi Tomas,

It looks like you are talking about the "Super" Scorpion. Correct me if I am wrong.
I built and flew a Super Scorpion a couple of years ago. I have since sold it to finance another project.
I thought the finish was not a good as it could be. I also thought it came out a little heavy, but then again, it is an inexpensive kit as far as big jets go.
Mine flew fine after a few CG and trim issues where delt with.

Let me know if you have any questions regarding the jet. I have a lot of pictures I took during the building phase if you would like to see any.

Regards, Bryan

RE: Scorpion from AD-Jets
 

Another try to upload picture

RE: Scorpion from AD-Jets
 

I don't think he is talking about the big Scorpion - i had the regular size one with a 30 lb turbine and it needed more. The guys that are happy have 36+lbs. The recommended thrust is was too low.

They do fly well once the CG is right and needs to be right on the gear struts to work. This is esp important for landings as a forward CG will lead to the nose dropping on landing and that vicious bunny hop down the runway.

If I were to do it again, I would buy an all white and have it painted. It would turn out nice then as long as the paint didnt add too much weight.

PaulD

RE: Scorpion from AD-Jets
 

I had to test if the turbine fits, I had to make some modifications, first cut of aprox 10mm of the rails on each side and reinfoce them with 5mm ply to get the turbine higher for better clearance from bottom of the fuselage. Now it looks good. I have made the hole behind turbine larger so I can rise the tube a little , I will use a 65mm tube from CS turbine i Sweden.
The tube is optimized to give maximum thrust at 300km/h , but I have to get down the area of the air intakes to 50% in order to get the airflow correct.

RE: Scorpion from AD-Jets
 

HI Paul ,
yes I´m taking about the smaller , the big one is too big and heavy for mi taste, I want the power / weight better than 1:1.

RE: Scorpion from AD-Jets
 

Here are a few pics of mine flying this June 2010. I have a 31lb Ulysees turbine in her and she flys well

RE: Scorpion from AD-Jets
 

I started to make the air brake, as I prefer servo before air cylinder I changed the design.

RE: Scorpion from AD-Jets
 

nice low height flying there.

RE: Scorpion from AD-Jets
 

I have made a hatch in the nose so i can use the loong nose for accus and rc equipment . I have reinforced the hatch with carbon cloth and designed and made hinges in our CNC mill from 2mm G10 plastic. The opening is as large as possible. Will have 3x 2s5000mAh for radio and turbine, a 3s 2100mAh for lights and smoke.

RE: Scorpion from AD-Jets
 

O have started wit the wing. The supplied hardware is not up to mi standard, I have designed new hatches for wing servos so I can use ballinks. I have used Traxxas ballinks for the ailerons the uses M3 bolt and M4 rod. They are short and sloop free. Dual rudder horn is also new in 2mm G10 plastic.

RE: Scorpion from AD-Jets
 

The flaps are made internal , new and cnc miled.

RE: Scorpion from AD-Jets
 

Hi Tomas
Looks nice.
Do you need more power? He He He...:D:D:D

Regards
Anders

RE: Scorpion from AD-Jets
 

Tjabah Tomas!
If you need even more power, buy an AMT Olympus Hi,hi,hi.;)

Lasse P

RE: Scorpion from AD-Jets
 

Hi all !

Seems to me that 16kg engine on the "standard size" Scorpion is atoo-much power configuration !!!

Here in France I've seen some Scorpion flying flawless and enough powerfull with 12-13kg class turbines. The big Scorpion isflying very well with a 16kg class engine (around 20kg at take-off), and it's just few month ago that I've seen a P200 engined Super Scorpion, and this one seemed to have infinite power in it !!! But it was heavier and less easy to fly.

For me, fitting a 16kg class engine in the standard Scorpion will only increase the total weight of your plane, need increase of petrol capacity. That will not enhance the flight performance...

Lighter is better !

RE: Scorpion from AD-Jets
 

Yes you are right about that...
But Tomas is using a 20Kg just for safaty...:D



/Anders

RE: Scorpion from AD-Jets
 

Well,OK... If it's for safety purpose...http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

RE: Scorpion from AD-Jets
 

Yeah! It will be extremely safe!
Jonas

RE: Scorpion from AD-Jets
 

Yes safety is mi first priority, need to be able to go vertical if i´m to slow on landing, and as we live so high up in the north we need more power to get up! :)

Well the nice think is that the big Hawk 190R will ad weight some 900g , but as i will use only 3l fuel i save some 200g , and I will fly for over 10 min on that fuel , that is longer than with regular 12-14kg turbine. The Hawk takes 230ml at 100N thrust :).

Will let you know it there is too much power , but I do not thing that :).
I´m building position lights now!! Landing lights is first, lots of work as the are no wing tanks on the Scorpion.
I have made some templets for cutting out those lights. I use 1 W diodes and 10mm reflector.

RE: Scorpion from AD-Jets
 

Hi Tomas,

Nice work!

I would love to see a picture of the machine you are cutting the fiberglass parts out with.

Keep the posts coming.

Bryan

RE: Scorpion from AD-Jets
 

My Scorpion, which I built in August of this year had a great finish on it. I dont know why but I seem to get lucky... other than the seams which were OK, visible but blended and filled OK, the finish itself was excellent.

With the BEhotec 180G, the plane flies GREAT. I wouldnt want any less... take ofs from short grass runways where I fly are quick (300 feet easily).

AJC

RE: Scorpion from AD-Jets
 

HI Bryan
here are couple of pictures, it´s a homebuilt. cost same as a jet :).

RE: Scorpion from AD-Jets
 

O have been cutting hatches yesterday, wet nice and the function is excellent, I´m gluing everything of the G10 plastic with Thin ZAP CA and it´s rock solid.
Will try to glue that inside the fuselage today.

RE: Scorpion from AD-Jets
 

Thanks for the support :),
I believe that with big turbine it is possible to fly slower than with a small one as you don´t need to have speed for perform a maneuver you have the power to that. Compare new and older full size jets , the new ones can fly much slower at high alfa and lots of power. For grass field it´s necessary with 1:1 thrust ration for descent take off.
Off course you have to handle the power with respect , dive with full power and then pull up is not a smart thing to do :).

The nice thing wit the Hawk is that it takes less fuel than anything else on the market at given thrust.
For example: At 100N needs the Hawk approx. 230ml/min, the rest of turbines produces some 30N at that consumption, and they will take around 400ml/ min for 100N .
So only drawback is that the turbine is 800g heavier than turbines in the 16kg trust range. I can put in a 2 l fuel tank and fly the regular 7-8 minutes but that is no fun :).

RE: Scorpion from AD-Jets
 

I have mounted the hatches how and they are working as planed :).