Blade47

Almost done ..I can do the final sanding and prep-work to start covering until the retracts show up baaaaaah [&o]

jetpilotrich

Flew the Flanker again today! It was awesome! Rock solid stability in all phases of flight. This plane does beautiful jet-like rotations during the takeoff roll. It has a phenominal roll rate but is very smooth. I used about -20% EXPO. for the ailerons and adjusted the rudder pushrod so both rudders angle inward very slightly... the constant load on the rudder surface should help prevent any flutter. In the landing flare there is plenty of elevator as long as the plane is balanced properly. My plane sits on the wheels on cement with an empty tank.... if the nose is raised about 1" the tail will fall... this is normal! As Alex has indicated the fuel and thrust will keep the nose on the ground. I will send more pics soon!

Rich

Bob.R

My Feedback: (2)

Cool looking plane - nice job. How did the Jett perform?

jetpilotrich

The Jett performed flawlessly as they usually do! It was turning 14,300 RPM as advertised on the ground before flying. I did perform several go arounds after practicing some approaches... the power was always there instantly when I needed it . I would not use any other engine on this kind of airplane. You can buy cheaper engines but not better ones especially for this kind of application.

jetpilotrich

Here are some more Pics!

Rich

smchale

My Feedback: (67)

[sm=thumbup.gif] Looks great!!!!!

bob27s

My Feedback: (19)

Way to go Rich!

Glad to hear ya got her in the air...... and most importantly that it flys as good as it looks

Bob

Blade47

Bob 27 ...A Q for you .... has anyone done a study on the the thrust given off by the muffler? seems that todays muffler with the directional exhaust port it would perform like a directional nozzle.. Hmmm just pondering.

bob27s

My Feedback: (19)

Some time ago I recall some FAI folks studying the thrust gain from a tuned pipe. Based on some of the same concepts that exhaust augmenter tubes (used on BIG radial engine exhaust years ago) were design around for thrust recovery.

As I recall, the thrust effects of a tuned exhaust are pretty minimal.

Rudeboy

All sorts of gains can be made on the HUGE WW2 plane engines... cooling drag is supposed to be a major issue too, or at least it was. If you look at radial engine powered RENO racers of today, you notice the absolutely MINIMAL air inlets they have for an absolutely monstrous engine. I mean, they've got like a 1.5" gap around the spinner to supply cooling air to a 4000 hp engine, go figure... They can get away with it because of "pressure cowling" and extensive ducting. They even try to recover the energy lost by the engine to the cooling air by converting it to thrust... the thought is that by heating the air you add energy to it, and if you add energy to it there must by a way to convert it to thrust.

For our applications the gains are minimal, although the idea of pressure cowling has existed for a fairly long time in the FAI world. Most of todays designs use "something" that can be descibed as a pressure cowl... but the refinements are nowhere near of what the RENO guys have achieved.
If you look at todays FAI planes, it is hard to imagine that a lot more can be gained from airframe refinement... but there is still some room for improvement in increasing cooling efficiency and reducing cooling drag. The idea is that a well cooled engine can be pushed even further than what we see today.

As for the additional thrust from the exhaust: that should be fairly easy to calculate. One can "guesstimate" the amount of air swept each stroke, and one can measure the amount of fuel burned each stroke. One can also determine the amount of swept air fairly correctly by looking at the sort and amount of fuel burned per second (air to fuel ratio). Since both the air and the fuel get pushed out the back a certain number of times per minute through a hole of known dimensions, one could calculate the thrust.
But in any case, like Bob said, the effects are going to be minimal.

bob27s

My Feedback: (19)

Good post.

The best cooling is actually achieved with low velocity, higher pressure air.

If you notice on full scale F-1 and on models as well, that the air intakes are pretty tiny. They really do not have to be large. The high speed air is allowed to expand and is slowed down inside of the cowling. Baffles direct air over the cylinders.

A popular misconception - if you look at the 'cooling inlet' on a Cessna 152 or 172, you will not see cylinder fins. The air is directed up over the engine, across the cowl and plenum, and then expanded downward through all of the cylinders.

Real good article by [link=http://www.supercoolprops.com/ARTICLES/ducted_cooling.htm]SuperCool on the subject [/link] (and many other subjects are well coverd too)

Kinda off thread topic, but some of ya speed guys may find it good lunch time reading

picard1

My Feedback: (2)

After finisihing a balsa usa 300 extra for a friend, i'm back to my su-27. Did anyone add any light plywood between f1-f2?. THat area seems a little week for supporting the engine. I should be starting my retract install with robo struts and I'll shoot photos of the process and post them as i go.

Congratulations on your flight jetpilotrich !!
Are thoses LED"S in the tail cones? sweet!!!!

jetpilotrich

The tail cones !QUOT!afterburner!QUOT! look is nothing more than a bright fluorescent/neon sticker trim you can get at the hobby shop... I just cut it in a circle with scissors ... you could also use a bright Ultracote. Also I would recommend Ultracote over monocote... Ultracote stretches and bends better.

I think you are referring to adding some light ply between F2 and F3? If so.. none is needed.. however I did add tri-stock all the way around the octagonal firewall in the fuel tank compartment as well as the tops and sides of F3 (both front and back). The sides of F3 are not critical since most of the G-loading will be positive. Alex has designed this thing well... early on I stress tested the airframe by lifting the entire thing by just the engine mount! Its strong!!! The fuselage skin gives the plane its rigidity and strength.

Note on the gear! I would not use a 5/32!QUOT! Wire! Especially if you are flying off a grass strip! The thinner wire will bend to much especially the nose gear. !QUOT!FLY BOY DAVE!QUOT! said it best about the Cermark F-16 the nose gear is like a !QUOT!wet noodle!QUOT! with the weight of the engine. The SU-27 has a long nose strut and will be totally useless if you use a 5/32!QUOT! wire.

I highly recommend using a 3/16!QUOT! wire for all the struts!!

I am going to post a gambit of pics and modifications I made which I think improve an already Great model.

Keep the questions coming!!

jetpilotrich

Sorry for all the "!QUOT!" that appeared in the last post! This RCU spell checker did that for some reason.... last time I use that thing! Here is the corrected post!

The tail cones "afterburner" look is nothing more than a bright fluorescent/neon sticker trim you can get at the hobby shop... I just cut it in a circle with scissors ... you could also use a bright Ultracote. Also I would recommend Ultracote over monocote... Ultracote stretches and bends better.

I think you are referring to adding some light ply between F2 and F3? If so.. none is needed.. however I did add tri-stock all the way around the octagonal firewall in the fuel tank compartment as well as the tops and sides of F3 (both front and back). The sides of F3 are not critical since most of the G-loading will be positive. Alex has designed this thing well... early on I stress tested the airframe by lifting the entire thing by just the engine mount! Its strong!!! The fuselage skin gives the plane its rigidity and strength.

Note on the gear! I would not use a 5/32" Wire! Especially if you are flying off a grass strip! The thinner wire will bend to much especially the nose gear. "FLY BOY DAVE" said it best about the Cermark F-16 the nose gear is like a "wet noodle" with the weight of the engine. The SU-27 has a long nose strut and will be totally useless if you use a 5/32" wire.

I highly recommend using a 3/16" wire for all the struts!!

I am going to post a gambit of pics and modifications I made which I think improve an already Great model.

Keep the questions coming!!

hattend

My Feedback: (20)

I think by "LED" he was asking about the apparent reflection of something red on the tail stinger

I could be wrong, though.

Don

Rudeboy

HEY!!

Now there's an idea... a bunch of leds in the tail cones would look awesome!

jetpilotrich

That is the reflection of the floresent sticker!

Rich

bob27s

My Feedback: (19)

actually, I rembember a bit of a 'stir' in the jet forum where someone may have been developing high-vis LEDs for sudo-afterburner look. Might be kewl.

Bob

jetpilotrich

After the second flight, the next day, many of the guys at my field indicated that the stickers were very effective... it appeared that the plane really had the afterburners lit!

jetpilotrich

HERE ARE A COUPLE OF PICS IN THE AIR! QUALITY SUCKS BUT STILL KINDA COOL! WILL TRY TO FILM IN THE PROGRESSIVE MODE NEXT TIME TO GET SOME BETTER PICS!

RICH

bob27s

My Feedback: (19)

Now if those flight shots don't make me want to go down and finish mine up.......... nothing will !!

awesome Rich!

btw..... I sent you an email. Had an executable attachment. If you did not get it let me know
(some virus software blocks exe files )

Bob

bob27s

My Feedback: (19)

I had to do this..... something compelled me

Blade47

Hey "Snoop" you pull pitch to hard and popped your self to another state? how is your painting coming along?

jetpilotrich

That rules! I have to get the video out for everyone to view!

Rich

Blade47

Rich!! Can i ask you now that you have a few flight on your SU ...If you used the aluminum spar rod and if you did how have you routed your receiver antenna wire?

Seems that maybe one other person (may) have had a problem with the tube.