Dear fellow flyers,

I bought this CMPro Swallow EX-90 model last week. Planning to assemble it by this weekend. Power plant is OS 90 FX 2 Stroke.

My previous model was World Models Groovy 90 3 A, I had OS 120 III Surpass in it! But had to ground it due to following issues;
o Model was too much tail heavy, even after this BIG engine, dead weights in nose
o Not enough climb
o Terrible tuning of stabs & wings incidence angles, never could fix them right

Now I want your experiences from Swallow for its construction & flying.
Best regards,

Sunny.[/font][/size]

a 13x8 will be just fine, throw in a tuned pipe , and it'll do wonders

13x8 is way to small a prop, this engine can turn more...

http://www.os-engines.co.jp/english/...e/proindex.htm

I would go for the 14x10 on this plane, remember you want airspeed to keep up the acrobatics. Also throw in a little nitro (10-15 %) and you will have no problem turning that prop. Anything from 8500 and up is enough (not more than 14000 though). And a tuned pipe WILL do wonders...

I turn a APC 16x10 on my OS 120AX (tuned pipe) (10% nitro) at 9800 rpm on a Groovy 90 - unlimited vertical

wow !!! 16x10...... omg thats what a YS140L spins! ....

Well prop selection is not that big deal. We can check that once model is completed.

What I would like you people to contribute to this forum will be your findings, views, ideas & tips regarding assembling of this model & its flying characteristics.

Please also inform (for those who installed 2Stroke engines) whether you installed the engine in 45 degree angle or inverted??

Best regards,

Sunny.

Its a very nice engine and the weight is low, and it is not much bigger then OS 91 FX....Buy one you wont be dissapionted...

I dont know this model, but on my Groovy 90 (same family) I installed the engine at 90 degres (sidemounted) mainly because I use a tuned pipe, then it is easier for me to make a nice header pipe (Krumsheid GERMANY)

Here's a link to a build thread: http://www.rcmf.co.uk/4um/
Search for "Swallow EX On line build"

Pay particular attention to reinforcing the wing saddle area and the landing gear plate - both are EXTREMELY weak. Even w/ the ply doubler in the fuse wing saddle area, the fuse is prone to breakage at the forward canopy area on a hard landing. The gear plate will definitely come out on anything but the smoothest landing. Use 'glass or carbon in those areas and you'll be good.

The hardware varies from OK to junk. My clevises didn't fit the threaded rods (not that I was going to use them anyway). I replaced all of my hardware w/ adjustable horns, CF rods, swivel ball links, etc..

I've got a YS110 in mine and it flies very well. Make sure you note the addendum to the instructions regarding the CG location. I'm currently flying mine at 167mm. The elevator becomes very sensitive any further back, and expo is even nice at this location. The plane tracks very well and handles wind pretty well too. Good luck with it!

Tim

Make sure that you set up the ruder to be as solid as possible, they have a tendency to want to fishtail at high speed if your rudder is too sloppy.

As for propping it, if you're running on a standard muffler, I'd say 14x8, but if you go for the piped option yes, you can swing a 14x10.

RE: CMPRO Swallow 90 EX power plant - 8/8/2006 11:33:59 AM


BaldEagel
Super Contributor







Posts: 1156
Joined: 10/12/2005
From: Wychling, Kent, UNITED KINGDOM
Status: online Hi all, my swallow fly's rearly well once you get the C of G back to approx 170mm behind the LE, I put my elevator servo's in the tail, one either side, used Hitec 5245MG's to keep the weight resonable, the UC is not good broke mine on the first landing the front extended piece broke away from the main leg, now have a carbon replacement from Carbon Copy in the Uk they make a direct replacement UC, I reinforced the seating by putting an extra 1/4" ply plate under the orriginal with a fibre glass strip between the two and up the sides of the fus internally, no problems for the last twenty or so flights, I have had a overheating problem with the engine but that is the engine not the planes fault.

Mike

< Message edited by BaldEagel -- 8/8/2006 11:34:32 AM >

(in reply to haisanjafri)

Dear Tim & Rendegade,

Thanks a lot for your information. Kindly also tell us regarding;

1. Did you fuel proof the engine compartment?
2. Are you using Y pushrods on elevators or some assembly to avoid differentials
3. Where did you place the batteries?
4. Is 170mm from LE is the best CG point??
5. How about its knife edge hold??
6. Nose tracking in a loop??
7. Is .90 Size 2 stroke enough to pull un limited verticals or pipe required??

Awaiting your reply!!

Regards,

Sunny.

Haisanjafri

I know you did not ask me but:

1. No mine came with a coating of some kind I assumed it was a fuel proof coating.
2. No I use a servo on each half at the rear, as shown on other thread.
3. Battery is under the canopy in the space behind the rudder servo.
4. 170 is what I use but I do like them lively.
5. Knife edge is very good small amount of roll coupling but easy to hold, may be due to rear c of g.
6. Absolutly straight, according to what prop you have the side thrust is enough for a 14 x 7 that I use.
7. I use a Jen 91 which is more than adequate, on a Genesis mini pipe.

Hope that helps.

Mike

Hey Mike,

It was great to have your detailed reply brother!! Well I have started assmebling my model, I will keep you posted. I hope I will be able to make the test flight on coming Sunday or may be next...

Best regards,

Sunny.

Haisan

Thought you may like to see the carbon UC and the sprayed cockpit, the cockpit makes all the difference more comments about it than the plane at my local field, sprayed on the inside with a lexan model car body paint. Extra pic of the rear elevator servo installation.

EDIT: Until I looked at this pic I did not realise how dirty my plane was, must try harder.

Mike

1. Yes - it looked like it was done w/ something at the factory, but I wanted to ensure it was completely sealed.
2. I used a Dave Brown carbon pushrod w/ 4-40 music wire for stiffness. I also supported it 1/2 way back - no slop at all.
3. I moved my fuel tank into the compartment just ahead of the servos. My battery is velcro'd to the front of the former just ahead of
the servo tray.
4. 170mm was just a tad too far aft for me. I'm at about 166-167 and like it a lot better. My elevator was too touchy on landings at
170, and my knife edge needed some elevator to hold a line. KE is pretty neutral now at the current cg.
5. KE is very easy to hold, and only needs about 1/2 the available rudder travel. Tracks nice and smooth!
6. Loop tracking is good too. It needs a bit of right rudder on the uplines to counteract the torque, but it's easily managed.
7. I flew mine originally w/ a Saito 91 and it wasn't enough for good pattern performance. For sport flying it would have been fine,
but it was definitely lacking in the vertical. Of course, my Saito was dying at that point (rocker pin stripped - I didn't know it at the
time), so maybe it would have been adequate if new. My YS110 has more than enough power for any pattern flying that I've tried.
I'm flying it w/ a 14x10, and it's great, except that I end up flying me level flight at really low throttle settings to keep the speed
down.

Hope this helps!

Tim

Hasian

One thing I failed to mention was that out of the box the logitudinal diaheadral was out from the positions in the fus I would have had 2 deg of negative incidence on the tail, this would have resulted in up elevator trim whilst flying straight and level, needs to be checked.

EDIT: This seems to be the norm in all the ARTF that you get now days the incidence's seem always to be out, this was the same on my Jarama Javelin S90 and my Graupner Extra 300L, the Extra flys as if on rails first time up, I did convert it to electric but came back to the fold with a Webra 80 (not made anymore and came out of one of my helicoptors)

Mike

Another thing to note in flying the Swallow is it floats on landing. It does not require a hot approach. Stalls are very stright forward and recovery is immediate. No tendency to drop a wing. Its my first pattern plane. I wanted to compare pattern planes to see if there was any difference from the .90 size scale aerobatic planes I had been flying. Answer: BIG TIME DIFFERENCE!!! Much better flying plane! I use a Super Tiger .90 on a pipe. Its a wonderful combination with unlimited vertical. Knife edge is forever and dead straight. It has made me a much better pilot. Even got me out of 3D flying.

I think they have addressed the old fuselage breaking issue. Mine, which was about 6 months after the issue came up here on RCU had the doublers extended aft further and that area of the fuselage well reinforced with fiberglass. The gear system seems to be better, but in a big cross wind I clipped a runway cone and tore the gear mount out. On repair, I added a triangle support, but really did not need to do much else. Interestingly, the aftermarket post elevator horn (8-32 bolt type) was bent 45 degrees in the impact, but no damage to the tail. The hole the post went thru was not even elongated!

One other note, the color scheme is about the easiest I have ever seen to orient in the sky, both upright and inverted.

In all I am very pleased with the Swallow. I may even begin to compete next year with it.

bob branch

Agree with everything that RJBranchii said, if you need a steeper approuch on landing try both ailerons up, it spoils lift and adds washout so no tip stalling tendancy, it just steepens the approuch, I use a side slider on my Tx to give fine control for landing, its a fine flying plane.

Mike

Dear All Swallow Owners,

Thanks a lot for everyone for adding much on the topic.

I have almost assembled my model. Rgearding CG, I have installed 2 Hi-Tech 225MGs on the elevator just like Mike did! Model is extremly good lokking rather I will call it "SEXY"
Now what I have found is that there is no built in thrust on fuselage front former. I have installed the engine at 45 degree so I got the silencer right under the nose belly. I have inserted one washer each behind two ends of mount, question is that how you people manged to give the right thrust & how much would be sufficeint!! As I need to adjust the spinner back plate & cowl fitting accordingly.

At this stage I am pretty sure now even from the look of the model, that I have bought the right stuff & it WILL perform by ALL means.

Best regards,

Sunny.

Sunny

I found no thrust change was required on the motor.

bob branch

Really? Did you install the mount directly to the fuselage withthout any thrust? Are you sure you flying CMPro Swallow Ex 90?? Just to make sure please... & if its right then it means there must be some side thrust built inn... Please confirm the same..

Haisan

I installed one washer under each bolt on one T engine support as per the instruction manual to give side thrust, I have not found the neccesaity for any down thrust, but I have not finnished trimming the model yet.

In the instructions it says install 4mm washer, thats dia not thickness just to be clear, the washers I used where the ones in the box.

Hope this helps.

Mike

Dear All,

I have completed my model. Posting few pictures for alterations I made;

1. 2 servos on elevator to balance the mode properly & effective controls of elevators
2. Replaced supplied wheels with bigger foam wheels to save weight & improved clearance of wheel pants

My next post will be after Test Flight which will be once I complete break inn of the engine.

All the best to all,

Sunny.

Sunny

IMHO you ought to get rid of those turret connectors to the elevators and anywhere else you have them, perhaps they are OK on the throttle but they are not reliable enough for a patten ship, go for 3mm ball links for the best control.

The next time you put servo's at the rear for elevators try to get the pushrod parrallel to the tailplane to ensure correct geometary for both up and down operation.

Mike

Dear All,

Finally I test flew my model yesterday. Engine (OS .91FX) was brand new, & I am breaking inn it on the model from very first flight in air. So the power was almost 50%. But it lifted beautifully. All I had to add in trims was 2 notches up elevator & that’s all. It flies great, though I will post my views about aerobatics later once the engine is completely break-inn & model tweaked.

But even at 50% power, it was holding Knife Edge rather it was climbing. I think MY model is set slight tail heavy that’s why it was bothering in landings. But I will fix that!!

Things which I didn't like;
1. L key often fells inside the belly pan of the wing while fixing wing bolts, so have tied a string with L key
2. Pull Pull Cable horn snapped in first flight (POOR QUALITY)
& thats all so far!

Regards,

Sunny.