Pyolet

Chris, sent you a PM. Woody.

Jeremy_D

Looking good Chris!!

Here's a short teaser of the fun your in for once she's up and going!! It's a great plane to fly!!

http://www.youtube.com/watch?v=FXVgH98HZ0Q

General Jake

Thanks Guys for the encouragement and the building advice.

Woody, thanks for pm.

Guys, please note on my previous thread the servo I'm using for the rudders. I had incorrectly listed my rudder servo as the HT-125, that was incorrect. I have since corrected that thread to the servo I have installed: HS-5125MG (Metal geared).

Here's the spec for the HS-5125MG:

Motor Type: 3 Pole Ferrite
Bearing Type: Dual Ball Bearing
Speed: 0.17 / 0.13 sec @ 60 deg.
English Metric
Torque: 41.66 / 48.60 oz.in (4.8v/6v)

I've used this servo in my Skymaster F/A-18, Eurosport Typhoon, and Hotspot. This servo has always been good to me, and have never had any problems with flutter or servo failure.
My bud, Major Woody who has two of these servos on the rudders, has something like 100 plus flights with his Skymaster F/A-18/Titan and has not had a single problem. Maj Woody pilot's that jet to the extreme, full throttle until it's time to land. If these servos weren't up to snuff, they would have failed on his 18.
Once I get this jet airworthy, I'll take it easy until 10 successful test flights are complete.

I do appreciate any concerns and please keep them coming....Even though I've been building and flying Turbines for 10 years, it's always nice to have another set of eye's.

Can't wait to fly her!

Jeremy, nice video...your 22 is awesome!

jeff sewell

My Feedback: (1)

Hi Chris,

I used some JR 4kg metal gear mini servos at 15 mm depth in mine without problems. Keep the horn on the servo short and linkage play to a minimum. or better still, none at all.

It's a really solid performer in the air...

Cheers

Jeff

www.zedjet.com

General Jake

Jeff,
I have a few questions. What is the weight and CG of your 22 and do you know how many ounces the two stock fuel tanks hold?


Well, I decided to change out my rudder servo. Due to all the emails and PM's regarding flutter of the JL F/A-22, I'll change out my Hitec servo to a larger more powerful JR 3421. This setup will use a metal gear horn, stainless rods and little to no slop.

Prior to doing this change, I plan on doing some wind tunnel testing to measure differential dynamic pressure there is between the two fins. Hopefully I'll be able to get some good results.

Stay tuned!

General Jake

I just replaced the rudder servos from the Hitec to the JR 3421's.

3421 : Specs

Type: Mini Digital
Torque: 65 oz/in @ 4.8V , 75 oz/in @ 6V
Speed: .18 sec/60° @ 4.8V, .15 sec/60° @ 6V
Dimensions (WxLxH): 0.58 x 1.30 x 1.02
Weight: 1.04 oz
Bearing: Dual ball bearing output
Motor Type: Coreless

jeff sewell

My Feedback: (1)

Hi Chris,

Not weighed it yet but estimate around 27 pounds...

The total capacity of the tanks are nearly 110 fl. oz (us) or 3.2 litres

My CG position is 120mm from leading edge at the wing root; when inverted it only needs a touch of down elevator.

The elevators need to be set at 10mm up from the neutral position for straight and level flight. I know that this would appear as 'nose-heavy' but it's not!

Mine is Merlin powered and the tanks give me about 8 mins flight time.

I used the JR 3421's on the aileron and rudders; though not the SA variant.

I hope this helps,

Cheers,

Jeff

General Jake

Thanks Jeff, that helps allot!

So no problems with the rudders, any sign of fluttering? I have the Titan SE going in mine, I think the Merlin is in the same ballpark for thrust??

The Titan SE puts out 34 pounds and I expect total weight empty will be 25-27 pounds. It's hard to believe the two tanks are 55 ounces each, they look so small..
Thanks again,
Chris

General Jake

I added two ducted fan 11 oz fuel tanks directly above the main tanks. Each DF tank feeds the main tank below adding 22 oz’s for a total of 132 oz, plus the BVM hopper. The Titan can get thirsty at full throttle so I wanted to add extra fuel for safety.

I decided to keep the entire fuel system within the aft half of the fuselage to limit CG shift. A benefit of this is, all fuel lengths are short, which should help the fuel pump....

General Jake

2

jeff sewell

My Feedback: (1)

Hi Chris,

I've had no flutter problems on the rudders at all so that's good.

Yes, our engines are similar and the performance is excellent, although my engine is a thirsty one too! I like to set the timer on new jets to about 5 mins and then land. I then check to see what is left in the tanks so I can judge the total flight time and alter the timer accordingley

As Jeremy Daly first advised me; keep it close for the first few flights until you get used to the shape!

Cheers

Jeff

Jeremy_D

Yeah that profile can be interesting....I find at certain angels the rudders blend into the fuse and I have one big flying grey plate!!

jeff sewell

My Feedback: (1)

General Jake

Last night I finished/tested the fuel system, and hooked up the main wheel brakes. The two half's of the fuse are now screwed together, this jet is huge!
Next on the list will be the Titan installation and bypass.
I'll post some pictures later.

Chris

jeff sewell

My Feedback: (1)

Wait until you get the wings on too...

Jeff

Pyolet

Guys, second all your comments on the JL F-22. It is an awesome bird, my favorite flier, and it'll gain popularity as more see it in action. 10mph to 200mph...don't know of any other scale jet that can do what it does. And it's tough too.

I did a basic build thread on another site back in March since RCU still won't accept photo uploads from my Mac...duh. Here's the link: http://rcjet.net/forum/showthread.php?t=1358

Over 70 flights on my Raptor. Switched power from Artes Super Eagle to my Artes Rhino 5 flights ago and all I can say is....***W i waiting for?! The extra 6 pounds of umph really make a world of difference without much more fuel consumption. It'll now hold 45deg hover in a 10 knot wind. Unless you run derated thrust, I'm going to recommend against using the stock JL pipe with the Titan. It's P120 sized and mine started to burn through at the splitter after 60 flights on the Eagle. Got my Rhino pipe from Tam and it still works with the JL bypass.

Chris, your planned fuel load mod should be more than sufficient for the Titan. I added a single 16oz hopper to the stock tanks and even with the Rhino, get 7 minute flights with 2-3 minute reserv and expect the Titan burn will be similar. I fly at mid throttle most of the flight with full power only needed for verticals and occasional high speed passes.

Agree that the airframe is tricky to keep oriented at times, but the good news is that it's no problem to keep it in tight and use the vertical...pull her hard without any worries... just turns and goes where you point her.

Have prototype single axis nozzles ready to install and will keep you posted here if interested. Aloha,

W.

Jeremy_D

Hi Woody,

Long time no hear!! Hows the vectored nossels looking? can't wait to see them in action!! How's bills Raptor going?

General Jake

Hi Woody,
did Tam work with you on the dimensions of the tailpipe?

Please feel free to post your vectored thrust pictures here, I'd like to see them.

Chris

General Jake

Here's the intake, bypass and split exhaust. I added the FOD screen as part of the intake.

General Jake

Getting to the electronics: Two battery system from Electrodynamics -EDR-108 Pow'R Back'R

http://electrodynam.com/rc/EDR-108/index.shtml

General Jake

I also added the GEAR Manager; this little device opens up some channels on my receiver and prevents the gear accidentally raising.

http://electrodynam.com/rc/EDR-125/index.shtml

General Jake

No more updates until Monday, I have to go fly this for work this weekend. Life is Good!

meps

My Feedback: (10)

Interesting work Chris. What kind of work do you do? I'm the guy that bought your P-70. I haven't run it yet as I'm still working on the airplane.
Steve

General Jake

Hi Steve, sent you a pm.

Pyolet

Chris, I just called Tam and told him that I wanted a JL F-22 pipe sized for the Titan/Rhino and he had it ready to ship in a few days. He has all the dimensions of the Raptor as he had the prototype bird. The Tam pipe mouth fits around the outside of the bypass instead of inside like the JL pipe mouth. It's got a wonderful full scale growl at Rhino full throttle and I have a lot more confidence to let her rip now.

Please post how the ED Gear Door Manager works out for ya...I want one but want to hear feedback first.

Jeremy, Bill's twin Raptor is still rockin. His top end beats mine although I've got him on takeoff performance and vertical. We had all 3 F-22's up at once in formation last Sunday during the Blues Angels morning warm-up....Bill's, mine and Mike's Christian Diffusion. I think that's a first. But talk about tough keeping orientation though...OMG!!!!

Will post vectored nozzle photos in a few weeks. Aloha, W.