hmjets

i have a masterfly f4 he still in the box since 1992. the CG is 34.5 cm of mediun cord seeing from the leading edge wing root.

Larry K

Johnny, I flew this particular model for at least 4 seasons in it's previous life as a ducted fan. It was powered by two BVM .91s with Viojets and BVM F-16 ducting. I believe it came in around 27lbs dry. It flew like a trainer plane! It was very forgiving and even with many engine out's it still had no problem. The C.G. was perfect when I flew it, but I'm not sure of the location. On takeoff it did not jump or lurch off the ground like some F-4's. I would ease up on the speed to be safe. I think with a little weight as a turbine, it will fly even better.

Good Luck!!

Larry

JetflyerJ

My Feedback: (67)

Thanks Larry and hmjets. My CG was wrong going by that measure.

yeahbaby

My Feedback: (21)

Johnny

it's probably just the angle of the photo on deck but it appears to me that the incidence on deck is too flat. that could delay rotation, causing severe pitch up at take off, or worse yet exceed tire speed.

a slight positive stance on deck wouldn't hurt, especially with the Peggy trying to push her down the runway possibly compressing the nose strut and worsening an already flat AOA.

I'm sure the bro's out in Germany have better guidance and look forward to hearing / seeing the first flight report. paint job looks sweet, that's one sexy bizatch!!

good luck

Buck

Kevin Greene

My Feedback: (85)

Buck has some excellent points and I also agree that you may need more positive AOA on the nose---But here are a few things to ponder...If your Rhino was built dead on scale the main gear will be located in a position that hinders rotation with our models...That position is pretty far back if built scale..The thing is that no one here has stated where the main gear is located on Johnny's F-4---Is the main gear in the scale location or was some "fudging" done to allow for better rotation...If the model rotates smoothly then chances are the gear was moved forward a tad. (Which is what I would actually want) If the model leaps from the ground, even though you have sufficient positive AOA on the nose, the gear is more than likely in the scale location...Provided you have your CG on the money and not too far forward...Maybe all of this will be of some help as to what to somewhat expect on that knee knocking maiden....

Kevin

JetflyerJ

My Feedback: (67)

I do agree with Buck and Kevin, the AOA has to come up. As far as this Jolapy being scale, it is not even close to scale. This thing was made to fly, they tweeked all they could for it to fly, kinda like Byron did with that big F-15. I'll make sure that the AOA changes this weekend and try to fly it.

Thanks again.

DaveMatthews

Johnny,

This may help

http://homepage.eircom.net/~skycam/L...its/videos.htm

Take a look at the CJM big F-4 video of my 1997 model. As you can see not much AOA there, but got off fine.

Cheers and best of luck with the maiden.

Kevin Greene

My Feedback: (85)

----It sure looks good though, Johnny!!! I wouldn't mind havin' 'er in my hangar!!! Let us know how the flight goes...

Kevin

PhilLin

My JHH F-4 is only 68-inches long, but it is probably among those closest to scale. There are a couple of points that might apply to your larger F-4:

1st, The main gears are quite far back. In elevation view, if you draw a line from C of G to ground contact point (estimate its height above wing), I get about 43-degrees instead of the 20-25 for easy rotation. Beside increased AOA setting mentioned in above post, I would make sure you have the recommended tailplane deflection to get airplane nose up. And don't forget to put back on hi-rate when landing, if dual rate elev is used, or it tends to come in hotter even with flaps.

2nd, my F-4 need flap to elevator (for nose up) mix for landing. Again enuf elev travel is helpful so you can still control attitude. You probably know these already from your smaller F-4. Good luck with your maiden.


Phil

Patrick Frost

My Feedback: (88)

Here are some pics of me and Tim with General Cherry who flew Phantoms back in Vietnam. He flew a camo scheme F-4 very similar to mine and Johnnys. I love my Phantom more and more after each flight. -Patrick

Miniflyer

Hm, i've always been wondering why everyone is making such ugly high alpha nosewheel struts on the F-4. It just does not look right...

Johnny, don't worry about the alpha, leave it as it is, it works out just fine. All the phantoms here are flying with scale length and scale alpha. (The one on the far right in the white and blue was done by my comrade according to McDonnell factory drawings, it has scale strut length and aoa). Noone has any sorts of problems and they all rotate smoothly.

One more flying hint, coming from a full size F-4 driver. The real thing usually does aft stick takeoffs. Line up with runway, spoolup, release brakes when passing 80% and pull full aft stick. Wait until nosewheel unsticks and then smoothly release on the elevator. Hold the nose up until the plane flies off on its own.

It works for the models just like it does on the real thing. Key is to hold up elevator during the entire taxi run to unstick the nosewheel as early as possible. Give it a try, that way you don't have to pull tricks with an ugly nose strut setup :-)
I'll get back to you with throws and CG tomorrow
Best regards
Hank

Kevin Greene

My Feedback: (85)

It actually is right for carrier based F-4's and BVM's F-4 has done it the best---You hit a switch to extend the nose strut to full length for takeoff as done in full scale carrier ops...BVM's F-4 strut accomplishes this with air...

JetflyerJ

My Feedback: (67)

Those are some cool pictures Hank, thanks a bunch. I'll be doing the maiden in the next few days and try to have or post a video of it, if not some pictures. Once again, thanks for all the help. Hopefully, Michigan Jets will be the first meet for this beast

Miniflyer

Kevin you're right, but i've seen the strut a lot on the long nose F-4E and F variants....that's just off and looks bad. My opinion...and it works scale if flown correctly :-)

Johnny, i'm standing next to my comrades plane now. Locations and throws as follows:

CG: 31cm from wing root on fuselage (very front, not the front of the small part that is molded on!). +/- 1cm makes no difference. DO NOT go beyond 33cm or it will get mushy and tailheavy!

Throws:
Aileron 2.8cm up, 2.4cm down
Elevator +/-3cm on LE, slight "up trim" for neutral
Rudder 7cm both sides at TE bottom
Flaps 5.6cm. Elevator goes UP (!!!) 0.7cm for full flaps down

Good luck on the maiden

Hank

PhilLin

Hank aka Miniflyer, can I bother you with also getting the root chord measurement at the fuse junction? I'd like to see how the deflections in a different scale F-4 compare. TIA!

Phil

Kevin Greene

My Feedback: (85)

You're right and they should pony up the bucks for the strut that will extend and retract---Hell, you've spent $$$$$ of dollars on the plane...Another few hundred to make it look right is no step for a stepper!!!

Kevin

Miniflyer

Phil, i'll get back on that as soon as i speak to him again, in the next few days.

Kevin, i think you got me wrong on that. The E and F versions (the one with the gun and the long nose) never had the extending strut. You can get along without it just fine, and there is also no need to make it longer, the short strut will rotate just fine if takeoffs are performed correctly.

Greets
Hank

JetflyerJ

My Feedback: (67)

Ok everything is set ( throws, AOA and CG ). We're having terrible weather down here so as soon as we get a break, maiden will take place. Thank you all for your help and I will post the end result.

Jason R.

Best of luck with it.

JR

Miniflyer

Just out of curiosity, how did you set up the nosewheel now? *g*

Regards

pbusa1400

nice flying jet johnny

JetflyerJ

My Feedback: (67)

The Beast finally flew today in the more than capable hands of pbusa1400 [sm=thumbup.gif][sm=thumbup.gif][sm=thumbup.gif] ( i left my b@l$$ at home, I was waaaay too nervous to do the first flight ).

First we had some issues with one of the wheels that was locked and everyone jumped in and got it loose. The jet was very very slow, I mean the only high speed pass I would say was at 35 MPH TOPS, we all thought that it was history but she hung in there and climb to about 200 ft after 3 minutes at Full throttle than POOOOFFF ( Deadstick ) ran out of fuel, we all said bye bye.......

She glided to a beautiful landing, we were all shocked to see that its such a baby. My BV F-4 would've been so history, its not even funny of how slow this thing flies. We have to find out what the problem is because everyone at the field was saying that it wasn't pushing more than 25 lbs max.

So there you have it guys, after almost 5 years the Jolapy is a keeper[8D]

Thank you Pablo so much for the great job you did tonight.

u2fast

My Feedback: (37)

congrats johnny, im thinking twin titans, barry

Bryce Watson

My Feedback: (6)

[sm=thumbup.gif]

BlackCloud

My Feedback: (12)

Proof it finally flew. All I got was the takeoff since I pushed the wrong button and it only recorded on the small memory card. What do you expect from BlackCloud anyway? LOL
Congrats J. Now lets's figure out why you tried to fly it on a P-60 thrust?

http://media.putfile.com/Johnnys-Large-F-4