maverick pro

just gettingnready to get my old a-4 ready for flight.

what are the correct throws for all serfaces?

what tank to use for fuel?...this plane looks like the tank was monted in the front just over the nose gear.

no flaps but does this plane need them?

thanks...mike

Bobman

My Feedback: (5)

Mike,
I've been thru a couple of them, both old & newer (second generation) kits. I'll dig in the shop for a manual for correct throws tomorrow & post them if someone else doesn't jump in first.

The original had a Dubro tank mounted above the nosegear retract on the plate & a hopper tank back by the engine. Worked OK, but saddle tanks seemed to work better. I converted one to Sullivan saddles but had to move the formers some to accomodate them if I recall correctly. One of the "necessary" mod's is to open up a hole in the inlet ducting just in front of the engine so that extra air can be drawn through the nosegear cutout. Substantially shortens the takeoff run. I believe the later models had a larger intake area so this wasn't required. Area should be about 2" or so, and was covered in a builder addendum.

The sport wing performs well, the scale wing was, ummm...... "quick" to say the least! Keep the speed up in turns & especially on landing until you get used to it. They fly on rails when fast, but can bite you when slowed down. Split flaps looked good, but I really didn't see a need for them & they didn't do too much on takeoff or landing for me. I'd keep 'em off to keep the weight down.

Enjoy your Scooter!

Bob

maverick pro

hey bob....thanks for the info. i think this is the first generation. what was the problem with the fuel tank in the nose?

did it want to tipstall on landings?

thanks again...mike

Bobman

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Mike,

No real "problem" with the tank in the nose, just that the fuel draw was sometimes an issue depending on pipe / plumbing setup. Also, the CG change is less when the tanks are located by the fan unit. If memory serves me coorectly, Yellow made a set of saddle tanks for it, as well as the older BVM saddles for the Agressor series would fit without mods.

Yes, it will tipstall pretty easily when you get it slow. Just keep it light & up on the power curve & you won't have an issue. If the engine dies don't try to make the field.... just set it down quickly. The sport wing definately handled easier than the scale, but it also would snap if gotten to slow.


Good luck!

Bob

maverick pro

thanks again bob for all your help. i got this jet for a bang around. our field is small but i fly a bvm maverick pro from it so this thing should be ok. im going to use a o.s 91 with a dynamax fan and jmp pipe for power. i tried to fit a viojet with a bvm 91 but just dont fit.

well thanks again...mike

jedijingle

My Feedback: (45)

Hello, I know Shaun Evans aka Yellowaircraft here on rcu put a violett fan and engine in one. Yellow makes a specific inlet for the viofan and the A4. Im not sure if it was for the old version or the newer one or both. Give Shaun a call and he would be happy to give you the details. Cheers John

619-944-7574 Shaun

Pizzazz

My Feedback: (22)

Mike,

I pulled these throws from my old yellow aircraft manual.

Ailerons 3/8" UP and Down
Elevator 3/4" up and Down (Maximum)
Rudder 1" Left and Right

The only word of warning that I can give you is keep the speed up in the turns. Just about every A-4 that I have seen bite the dust was due to either slow in the turns, where it just feel out of the sky, or due to the engine dying, which again lead to a slow turn!

Good luck!
Greg

maverick pro

hey guys...thanks for the input on the jet. the inlets are all in for the dynamax so im goint to leave it the same for now.

the 3/8 up and down seems why it stalls in lowspeed turns. that just dosent seem enough. i know at high speed the ailerons would be ok but lowspeed mite kill it for me. i will beavel the edges to get more throw from them. are field is small so i will need to be able to turn tite at low speeds for landings.

well thanks again...mike

Shaun Evans

Mike,

Ummm.....you don't necessarily want to have more throw on the elevator than what's called for. 3/8" may not sound like a lot, but the ailerons are very effective on this airplane. Like it's full-scale counterpart, this A-4 has a roll-rate you wouldn't believe. The amount of aileron throw has nothing to do with the stall.

Speaking of the stall, you only need to know that it's abrupt. It is very consistent--and will stall the same way each time if the circumstances are right--but there's not much in the way of a 'warning'. This plane doesn't mush or buffet before the stall, it just tips out. If you know what the stall angle is, you can fly this airplane for ever and ever without a problem. Just make sure that if you're turning tightly at low speeds, you've got a good nose-down descent happening. Better yet, avoid tight turns like previously advised. This airplane will high-speed stall, too, if you overdo the throw or pull such a sharp turn that you load up the G's and achieve that angle in a tight turn.

It all sounds worse than it is if you just stay away from the dragon. My then 13-year-old nephew soloed (then got his turbine waiver) on one of these as his first jet. He got 83 flights on it before his uncle mortally wounded it. All he did was go up high and test the low-speed stall. The high-speed stall never happened with his particular jet (though it has on several of mine). BTW, it was powered with a BVM 96SE and Viofan. It hauled boodie.

Good luck!

maverick pro

hey shaun...thanks for the info.

i will keep all the same like you said and go for it. shaun whats the correct cg for this plane?

also do u still make arfs.

thanks...mike

Shaun Evans

Hi,

We don't currently make the A-4 in ARF form, but we make others. Bigger ones. The CG should be 12.5" from the trailing edge measured at the root for the sport-wing. Good luck!

maverick pro

thanks shaun....i think the jet has the scale wing. is the cg different from the sport? what jet arfs are yellow making? i hope the A-4 flys good and is a blast.

thanks again for your help....mike

maverick pro

hey shaun... did the 12.5 cg and the plane is vary tail heavy. i did it empty and upside down with the reciver in the nose and the baterry under the intakes. the battery is a small 4 cell. now with 23oz of fuel will this plane get really nose heavy?

thanks again...mike

jwfly

My Feedback: (2)

mav, what did you settle on for a CG for your scale wing...was that with tanks full or empty?, how did your A4 do? thanks! JW

maverick pro

hey JW...i never finished balancing and never tried to fly the plane. i never got a answer back from anybody at yellow so the plane is sold and long gone. but it was really tail heavy empty and vary nose heavy full. let me know if you figure out anything with yours and good luck.

thanks...mike

Shaun Evans

Mav,

Sorry I missed this old post. If you ever have any other questions that you post and don't get an answer on, give me a call. I'm away from the computer for long periods of time sometimes.

tkielty

Has anybody converted this bird to electric and if so what power setup ?