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Oct 25, 2014, 09:57 PM
Registered User
bri6672's Avatar
Quote:
Originally Posted by JetMang
Ragtop,

Lucky you to have this kit! We have an f-14 thats the same size (was built for the movie top gun, never kitted) and I think twin high power 90's are about perfect for the airframe size. I plan to build one some day and plan to power with twin 12s 90 setups. Just my 2 cents. 90s will be lighter and get better flight times for the same capacity packs compared to 120s. It's only about 74" long at 1/10 scale. at 1/9 scale I could see 120s making more sense. The key will be though having clean inlet ducting obviously and ensuring the structural rigidity.


Chris
+1 74" is a bit small for twin 120's.....
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Oct 25, 2014, 10:05 PM
Registered User
70 ragtop's Avatar
Thread OP
Thanks Chris
I agree and really want to keep it as light as possible. It's size is just perfect for the 90s just as 1/9 scale is perfect for 120-127s

Skyhawk
I hear you and know what you are saying.

The video below is what got me thinking about jets again. A $120 fan and a $120 motor that weigh slightly more than 1 pound ($140 motor used in video). This was the re-maiden, so most of the flight was part throttle as he trimmed it. Seems to have pretty good get up and go

I'm SLOWLY putting a little HK Diablo (Bandit copy) together to try out the JF 90 on 10 and 12S. Typical HK/China reworks to do, and I'm in no particular rush, so likely a spring flight. No doubt that plane will be a screamer with the JF 90 on 12S, and will likely be around 10 lbs.

Have a ways to go before I need to commit to a particular fan, just want to enjoy the build

BVM Agressor II - old jet with new power (3 min 7 sec)
Last edited by 70 ragtop; Oct 26, 2014 at 08:54 AM.
Oct 26, 2014, 11:41 AM
KingtechUSA
gunradd's Avatar
Nice project!

I say twin 90s. If you dont have the inlets for the bigger 120 fan then its just wasted weight with no benefit. You will burn more amps have less flight time and not have more thrust if the inlets only big enough for a 90mm.

I helped Bob F get his yellow F14 (about the same size) going with twin K60 turbines when he wanted to switch from EDF and the plane is not very big. I would keep the weight down and make her a good flyer that will be around for a while.
Oct 26, 2014, 09:33 PM
C-5 Flight Engineer
PANTHERFLYR's Avatar
Very nice project! I had a JM F14 and will say that you want to change out the original sweep drive (o-ring) to a worm drive or gear driven. The sweep on this model was and is known for not being reliable. The o rings slip and you will end up landing swept back. Dave Shulman actually had to land the one I bought with the wings swept back.
Oct 26, 2014, 10:13 PM
Registered User
70 ragtop's Avatar
Thread OP
That's a beauty!

Did you build the stabs per the plans, or beef them up? Turbine or DF power?
Oct 26, 2014, 10:23 PM
wannabe Jet guy
CRCJA's Avatar
The grey one was twin Ram 500 powered, the painted one was O.S. .91 powered and they both flew well, it is harder to find fuel location for the twin Turbine one. But since you are going EDF, you should be able to us the stock tank location for batteries. Twin 90MM would be a light but powerful set up.

Ralph
Oct 26, 2014, 10:32 PM
Registered User
70 ragtop's Avatar
Thread OP
I'm a little concerned about how the pivot rod is mounted in the stab, as build per instructions. Thinking Dynamax was the power of choice when this kit was made. Maybe later kits changed the install, or add some CF between core and skins??
If you guys build it by the book, no blocks, no CF under the skins, and flew it on turbines, I'm going to stop thinking about mods and just build it
Oct 26, 2014, 10:35 PM
C-5 Flight Engineer
PANTHERFLYR's Avatar
Turbine power, and as far as I know it was built per plans- I did the rebuilding of almost the whole jet after the swept landing
Oct 26, 2014, 10:54 PM
Registered User
70 ragtop's Avatar
Thread OP
Quote:
Originally Posted by gunradd
Nice project!

I say twin 90s. If you dont have the inlets for the bigger 120 fan then its just wasted weight with no benefit. You will burn more amps have less flight time and not have more thrust if the inlets only big enough for a 90mm.

I helped Bob F get his yellow F14 (about the same size) going with twin K60 turbines when he wanted to switch from EDF and the plane is not very big. I would keep the weight down and make her a good flyer that will be around for a while.
Thanks
The Yellow is actually a bit bigger. This one is 77" wingspan, and I think Yellow's is 88". Bob's plane looks like it flew great on the EVFs. Why did he decide to convert it?
Oct 26, 2014, 11:05 PM
C-5 Flight Engineer
PANTHERFLYR's Avatar
..mistype
Oct 27, 2014, 08:25 AM
KingtechUSA
gunradd's Avatar
He had a radio related crash over a year ago with his edf f14. He is building a new kit he had with twin turbines. I think his reason for switching is less down time in between flights not charging and lighter landing weight longer flight times more power.

He was having some issues though and not sure what he's putting inside it right now. He Scratch built new fuel tanks and all already. Was about ready for paint last time i talked to him.

Quote:
Originally Posted by 70 ragtop
Thanks
The Yellow is actually a bit bigger. This one is 77" wingspan, and I think Yellow's is 88". Bob's plane looks like it flew great on the EVFs. Why did he decide to convert it?
Oct 27, 2014, 03:43 PM
A-4 nut!!
skyhawk's Avatar
I personally think it's a mistake to go with 90's - but thats just my opinion. Whichever way you go - I wish you the best. I was trying to get enough together to buy that very kit as I lost my job and the new one doesn't pay as much. Oh well.

If you do decide to go 90's try to make it so that you could install larger fans without too much trouble - just in case you find it needs more.
Oct 27, 2014, 06:11 PM
Classic jets rule
AIR SALLY's Avatar
Rag I'm with you,not sure I would trust just a t-bar sunk into foam. I would balance the stabs too.
Nov 01, 2014, 06:51 PM
Registered User
70 ragtop's Avatar
Thread OP
Thanks Guys

Got the shop cleaned up today, and the Tomcat back on the bench. Today was a cold rainy day, perfect for working on planes

As I mentioned before, wing box area has a little twist, so blocked it, and locked it down up front, at the wingbox, and at the stab pivots. Not too worried, once everything is located, and locked in place, should be a non issue. Plan to add a little stiffening to tighten up the tail, and make up for the smaller inlets

Focusing on the stab pivots today.
I looked and looked the for angle of the stabs and couldn't find it. No mention in the instructions, no plans, and the two sides had different angles predrilled in the pivot blocks
Have it on good authority (invertmast) that the stabs are 2.5 degrees, or 90 degrees to the verticals. Instructions has a template for the verticals, and working backwards from that, placing the stabs at 90 degrees to the verts, the jig blocks ended up at 2.5 degrees....thanks Thomas!

Pivot bearing is a simple aluminum tube with a steel shaft. Thought about upgrading, but decided keep it light weight, and simple
Got tubes fit in the proper location. Drilled a #10 hole in the backside of the preinstalled bearing blocks. Injected hysol thru hole while rotating tube. Got good squeeze out all the way around, on both sides
A little clean up and called it a day
Nov 01, 2014, 08:14 PM
Pursuit of Happiness
Ron101's Avatar
you have some of the coolest projects going on here on RCG ...... love it
the p-38 is awesome but this one is my favorite, your going to have a great machine


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