apalsson

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Hi Ron,

I'm running a 5 cell system (6 Volt) in the Pepsi Chipmunk.
The tail group servos are Hitec 645MG on 6 volts which seems to give quite a good push to the control surfaces. Then again, it's a big rudder and quite a heavy plane.

Al the best

Ari

carlosponti

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V2PLUS10 could you post pictures of what your elevator looked like while framing. i am a bit confused by the instructions on the one i am building. i am assuming you build the Dynaflite chipmunk of course but i would still like to see what it looks like.

thanks
Joe

V2PLUS10

Joe,

I do not have any pictures of the tail section under construction. If you go to the beginning of this topic, and page through you will find a very good series of pictures showing the build by apallson. The kits we built from are from Apache Aviation in England, not the Dynaflite......Good Luck!!

Randy

carlosponti

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i briefed over the instructions and it said ribs on the root and tip extend full length i misread and though it said all ribs which you can see in the picture. whoops. the instructions are clear i just need to slow down my reading. btw i like the way you finished your chipmunk such a beautiful plane.

ronaldh

Thanks Ari,

I've been using the 4 cell system but will change over to the 5 cell soon...especially for the 1/4 scale Super Cub with long extention leads to rudder and ailerons.

cheers
Ron

V2PLUS10

Ron,

Still no opportunity to fly here. The weather is nice only when I am out of town...

I am using a 4.8 volt 1400ma battery for the radio, with Hitec 5625 digital servos on the rudder and elevator and JR 811 digitals on everything else. This is my first experience with digital servos. I put one of those little LED voltage monitors in the front cockpit so that i could monitor the battery without removing the wing and using a tester. Don't have any idea yet as to flight time before needing a re-charge......

how is the build going??

Randy

apalsson

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Last weekend, I finally ran up the G38 in the Papsi Chipmunk.
As I had made some modifications to the mufflers (see previous post), I wasn't sure what power or noise output I would get.

The mufflers consist of the stock can muffler with a short piece of 5/8" pipe brazer to the bottom, angling backwards and a briggs and stratton lawn mower muffler brazed on as a secondary muffler.

This combination proved great. The engine runs relatively quiet but still retains the deep "throaty" sound.

I ran a 20x10 prop and after two tanks or to, I got over 7000RPM and idle was only 1500 RMP or so. Most impressed.

After slightly richening the low end, I got smooth transition from low to high.

Not many excuses not to fly the plane now

V2PLUS10

Ari,

The Saito 180 with a Graupner 16-8 turned about 9000 on a slightly rich mixture setting. The plane weights about 14lbs, and I made the first takeoff at about 2/3rds throttle, and maybe went to "wide open" two or three times that first day, but only for a moment or two. You should not be lacking for power!!

Keep us informed!

Randy

Sheriff of Nottingham

hello ron,followed your advice and purchased laser 150.Could you tell me if you used engine vibration eliminators from apache,and did you use a nylon engine mount? Recommend prop size is 16x8,have you tried this,and if so do you think it was about right? Many thanks, frank

ronaldh

Frankfearn,

Sorry about the delay I wasn't aware of the new post until today.

Although I bought the vibration isolaters from Apache I never used them for the laser 150. The engine was mounted using a glass/nylon engine mount. I always have difficulty in locating the large size nylon mounts. Eventually settled on the Anderson type available from Inwoods. If you can't find a size big enough, a smaller size cut in half will do (as recommended by Laser). The nylon mounts seem to provide a certain degree of isolation and will shear off in a crash (unthinkable!) with probably less damage to the motor.

I also find a 16x8 glass/nylon prop from (Graupner) is so far the best. The Master 16x8 with narrower blades seem to rev too high with less pull. Haven't tried their K series yet.

Are you running muffler pressure?

Ron

Sheriff of Nottingham

hi ron, many thanks ,dont intend using muffler pressure ,according to laser man its not required.Did you run yours on pressure? Looking as though i will need to pack the engine mount a good way to achieve correct cowl alignment,will use some good quality ply.Not really keen on using dowels as the chap did at beginning of thread,may be perfectly a.o.k, but i prefer something more substanshle,maybe why my models always end up on the heavy side.What does yours weigh? all the best, frank

ronaldh

Hello Frank,

Yes, I run mine on muffler pressure but it's not necessary as most of the guys here do not use it. Just one more thing to go wrong I guess. Old habits die hard. Make sure cooling is adequate as 4 strokes run hot. Baffles to direct airflow over engine and cutting cowl open at bottom for air exit will be necessary.

I used MDF (instead of ply...much heavier) to bring the engine and mount out to meet the cowl line.

Model in the end weighed 13.5 lbs (profilm cover) which equates to about 28oz/sq ft. Try to keep weight down as much as possible. Flaps very good for slowing down landings...no tip stall evident even at very slow landing speeds.

Are you using their stock piano wire u/c. Working oleos might be a better option on bumpy grass fields. Have had to straighten mine several times. Wire getting softer? Apache sell oleos at about £26

Ron

Sheriff of Nottingham

hello ron, thanks for the good advice,this is my first laser engine so i want to be 100% sure of all aspects.Spent last 2 seasons flying martin bedding lazer 200 using os91 surpass and various irvine engines.Like i say first 150 so need to be sure. Chippie wing is finished with silver solertex and fitted with oleos ,going to start fuse closer to winter.The only thing i altered on the wing was the servo mounting,would much prefer to have servo heads popping out for ease and maintenance. Did you go with the rates that the manual suggests? I will attach some picts shortly. frank

Freff

I have just aquired a part built Apache Chipmunk project from a clearance sale. Unfortunately, there are parts missing and no plans or manual. I would love to finish this model as I know how good they are to fly. If anyone has any plans/manual they have finished with I would be more than willing to pay for them or any cost in sending. Many thanks in anticipation.

ronaldh

Freff,
Your best bet would be to contact Mike Lewes of Apacheaviation.co.uk direct. He is very helpful. They also sell separately different parts of the kit (crash damage!) I'm sure he will sell you copies of plans and manual. Do you know what version you have of the 3 types: Trainer(RAF or RCAF), Pepsi or Penzoil?

Freff

ronaldh

Thanks for the info. I have left a few messages at Apache but have had no replies. The kit is for the Penzoil.

ronaldh

Freff

Apparently, Apache is closed till the end of the month. Holidays?

I'm sure you will get a reply.

Ron

Sheriff of Nottingham

hello Ron, a few picts of airplane. Ive used a GP adjustable mount, had trouble obtaining any others, a golberg snap on spinner with which i found very cowl alignment very easy.Brand new laser 150,as of yet still unrun.Ive purchased 2 futaba 5kg servos as the manual suggests,not be long now before shes ready for the off.

ronaldh

Hi Frank,

Chipmunk looking good. The fuselage appears to be covered in nylon? My Laser is mounted identical to yours. What about cooling? Will you be placing deflectors in the cowl to direct incoming air over the engine as shown in the Laser instructions?

Sheriff of Nottingham

Hello Ron, i do intend to put baffles in the cowl to direct airflow,but im unsure what material to use, maybe some lithoplate? Fuselage will be covered in solertex as the rest of the model, pictures arn,t brilliant.Just in the process of doing a little detail in cockpit ,not too much though, a few instruments, pilot ect.Hopeing to complete and have a test flight before winter really sets in.Ive used heavy duty snakes for control surfaces,4-40 SIZE,what did you use? Cheers, Frank

ronaldh

Apache supplied steel rods for 'push rods'. I used them both for individual rods to each elevator half, ie two servos for elevators...overkill I guess! Pull-pull system for rudder. Tail wheel later modified to be driven by springs off rudder control. Perceptible fish-tailing movement in flight...could it be the pull-pull system flexing and giving slight rudder movement?

For baffles I used 1/16 plywood heavily fuel-proofed.

Ron

V2PLUS10

Frank and Ron,


For what it's worth I used old carbon fiber arrow shafts for push rods. I set up the rudder and tail wheel as described in the instructions/plans. I used a single pushrod for the elevator that forks near the tail and then goes to each elevator. Two complete pushrods would be a better choice. The forked one will cause different elevator throws if it is not exactly centered. The tail wheel really needs to be set up differently, so the throw can be varied and isolated from the rudder via springs, but the rudder control seems fine. My model also wags it's tail a bit. I've seen scale model P-51's do the same so maybe it is something that just happens with low wing models. After many flights this year my only real complaint is with the landing gear wire. It will splay out after a few landings, even with the Apache supplied struts, and is difficult to straighten. Heavier wire would be the solution I suppose. My model may be a bit heavier than most though with the Saito 180 and an onboard glow driver and battery.

You will find it a great flying model though. Let us know how it goes!

Randy

Sheriff of Nottingham

Ron and Randy, i think your right about fishtailing in low wingers,i fly a gangster 52 which as had nearly 500 flights, and every flight the tail wobbles, i thought it may have been a mistake in my building,but obviously not. Im going to go with the manual on the tail wheel and see how she behaves, i may well change it later.What does yours weight in at Randy? Im expecting between 13 and 14 pounds. Thanks, Frank

ronaldh

Well, well! All the time I thought it was just me with this fish-tailing in flight. Thanks Frankfearn and Randy.

Talking to a mature modeler about the problem of fish tailing and he also mentioned his Gangster 52 had the same peculiarity. Perhaps it's the canopy on the Chipmunk masking or blocking the rudder...does the gangster have a large canopy?

Will have to do something about the u/c wire. Four flights today and about 25 landings and take-offs and the 6mm wires are bent back. Our field is grass and a bit bumpy. nose overs are possible with the bent gear.

I'm flying with the cg at 5 inches from the leading edge at wing centre. Any idea what yours is Randy?

Ron

V2PLUS10

Ron,

I began with the CG as indicated on the plans, which I think is very near the front spar, but have since shifted the batteries from in front of the wing, to between the cockpits, so that would move the balance point back a bit. I felt that my model was a little nose heavy as I would run out of elevator in the flare, though I also had the throws set to low rates, and I wanted a little more response from the elevator and rudder in gereral. I even added a little weight to the tail, about an ounce of lead attached to the tail wheel bracket. That is one reason that I'd like to add a tail wheel assembly that is sprung etc....a little more weight back there. If I remember right my model weighed about 14lbs, but this was measured with a bathroom scale..someday I'll get one of those digital fish scales to weigh airplanes with.

Randy