kochj

MY wife and son are in Michagan, so the camera isn't here....
How can I lower my tank on this plane???
I will check into it....

Right now it builds up when it comes off idle...and, even with the ignition is stumbling at times....
Unfortionately, when running the OS twin, there is 2-idle settings to deal with...

1. When you lean out the idle with the airbleed, and then close it down with the throttle, it will run preaty decent, but still syphon..
When you advance the throttle, (like millimeter) it will then go on the main needle, and suck all that syphoned fuel that was sitting there into the engine...
THis is the loading up phase....

THe other option is, to not allow the throttle to close the carb enough to go on the idle adjustment, and try to make adjustments from there...
THis isn't a good thing though....

It is interesting, because, I can clearly hear the engine run on the idle screw (have to have it lean) and then advance the throttle (and hear it go on the main needle)
and you can hear the engine go lower and richer immediately....

ANyhow, I had to take the engine apart, because I noticed a bit of rust in it.
I even placed Airtool compresser oil in it....LOTS of it ...
Obviously I will not use that oil in it....I will pick up a better after run oil....

I didn't want ANY rust in that engine....
It will act like sand paper to the cyl. walls and rings... when it comes loose....

kochj

Perhaps I will do a full Gemini 1.60 twin post...but..
Interesting thing with that engine is that the connecting rods have to go back in a certain way,
or they will bind up... by not matching to the cap that you bolt to the bottom of the rod...

It appears that it is not perfectly 90 deg from the piston....It is slightly off center....
They must do this to affect the load....

I will have to take picts this..

Cheers...

zdsh13

Just started working on my chipmunk tonight, but after working on a 1/3 scale cub and a Lanier 87" 50cc extra I look at the chipmunk and it looks kinda small..... Oh well I'm sure it will finish nicely, plan to put either a Saito 1.50 or a 1.80 in her, I also have the robart oleo gear that will hopefully prevent the bending on the 3/16" wire legs.

Overall I'm happy with the kit quality, and look forward to flying her. I had a goldberg chipmunk I flew for years and loved it, hopefully the GP chipmunk will bring back the memories

zdsh13

My Chippy is all done, hopefully I'll get some nice weather to maiden before the snow hits.....

I opted for the Saito 1.50 and side mount, not 100% happy with the cowl cut out but oh well. Balance was close to right on with no lead added, my motor install was about 3/16" further out which helped some. I also replaced the hardware in the kits with heavier dubro arms and dubro 4-40 pull-pull kits.

I also noticed on my kit that I have a slight twist in the fuselage which slightly lowers the right stabilizer in relation to the wing. Nothing too serious but I would say atleast 1/4" out. How were all your kits??

GSNut

My Feedback: (8)

Looking Good

Be ready on that rudder on the ground in a cross wind it likes to weather vane, at least mine does.
Mine is hot with a Saito 1.80 in it, so the 1.50 is a good choice IMHO !

With that twist in it or one stab side low it will try to turn...... like the old free flight models were trimmed to do.... Best if you could repair if possible ??? Mine was fine there but had up thrust built in to the firewall.
I had to grind 3/8" in. off the motor mount.

zdsh13

Repairing the stab would be alot of work I think I will try it first and see how bad the tracking is in a loop, it will obviously want to pull to the right a little with up elevator. Looking at the fuse it looks like it was molded with the twist as there is no stress indications on the fuselage.....

With the fiberglass fuse it is kinda tough to remove some of the wing saddle to align the wing to the stab as the fuse is molded with a flange in the saddle.


I had up thrust as well...

GSNut

My Feedback: (8)

With the fiberglass fuse it is kinda tough to remove some of the wing saddle to align the wing to the stab as the fuse is molded with a flange in the saddle.


How much of a shim could you put on the wing high side in the saddle?? maybe ?

zdsh13

duh.... How come I didn't think of that [sm=spinnyeyes.gif] I would have to open up the wing dowl holes but thats not a big deal at all.

Thx..

yellerchamp

My Feedback: (42)

I like the struts, still flying mine its @5 years old, actually put two more flights on her today. I have a couple of 18x6 apc props if intersested. One of the best planes in my hangar...good flying...dan

GSNut

My Feedback: (8)

Keep us Chippy Lovers posted how it goes..

zdsh13

Completed the maiden on the chippy with a Saito 150. Pretty uneventful, not much trim needed.... Sweet airplane with the Saito 1.50, it does not have unlimited vertical but but has good penetration (was only using 5% nitro), for the sport flyer it is a perfect combination. Knife edge flight pretty easy and man does it snap well, it flies better than the Goldberg Chipmunk I flew back in the 90's.

My specs:
Saito 1.50
Mejzlik 16 x 8 (8650 rpm on 5% nitro)
Robostruts
CG - 5" from leading edge.
weight... need a better scale

GSNut

My Feedback: (8)

Here's to many more happy flights with your Chippy.
If you are as satisfied with yours as I am with mine then you got a winner.

Doug in Denver

PlaneKrazee

My Feedback: (14)

Still have one NIB, maybe this winter I'll assemble it.

kochj

About the wing alingment thing...

I had done some adjusting on both my main wing and my rear stab...
It was mainly in the fiberglass belly pan, in that the wings didn't sit equall...very small amount though....
I am a perfectionist...and Most wouldn't even think twice about it...

My main issue has been the Gel coat....Cracks very easily....

This has been when I pick up the plane when ready to run at the field.....

If you grab it right behind the main wing, there isn't any formers to prevent the fiberglass from compressing and indenting....then it cracks...

Not horrible though...but Then, I haven't had a composite plane before......

I am NOT a fan of that White brittle material, that is SPrayed on the fiberglass after it is dry, out of the mold....

It acts as a barrier, and makes the fiberglass holes dissapear....
I don't know what it is, or what it is called....

If anyone has ever busted up a Cowl, you will know what I am talking about....
The paint is applied directly over it....

Very lightweight, but once it cracks it never seems to be fixed right....

This white material seems to be what gives the fiberglass molds there stregth and shape....

kochj

I am wondering if the 17x6 isn't enough for the 1.60 twin...

I found I needed more power than what I had...

I had just enough power to get it over the loop.... Not used to that....Having to fly on the wings...

If you have a Really BIG aircraft, you can gain speed, but you really need a bigger aircraft to do that...

I want to do aerobatics, and I would like more power......

I will see what I do...

kochj

Perhaps I am not using enough flap, or comming in WAYYYY to hot (worried about tip stall)
but the landing gear metal is RUBBISH....Very weak/soft metal...

After they bend FOrward...and the rear of the wheel pants scrape the pavement.
It is himiluating, after seeing how nice it looked prior to landings...

yellerchamp

My Feedback: (42)

I have had mine for @ 5 years and have no isuues with fiberglass or landing gear?? I fly a older os 120 four stroke with 16x6 apc fly very well I dont use flaps for landings but we fly off grass, she just floats in to a 3 point landing everytime..

zdsh13

Where did you set up your CG? I have mine set at 1/4" further aft of the rear limit and it just mushes in a 3 point stance for landing with no wing wags at all. My 12X does a great job with the flaps, they drop down in a 2 sec transit time and adds 12% down elevator... works sweet.

The robo struts help too but I find that the shock absorbers should be a little more stiffer as they compress pretty easy. As for my wing alignment issues I do see a little roll coupling when I apply up elevator but not enough to worry about as I'm not flying serious IMAC anyways..... most of my flying has some form of lomcevak's anyways.... this thing tumbles very well

kochj

Hmm..

I had listened to a (know-it-all) at the flying field...and he said I had tip stalled it
when I landed and the wing droped on scraped the runway...I thought is was just wind, as it didn't seem like
I was going that slow....

I may have been flying it in too fast....but even so, I don't see why it would be that the gear "flexed" as much as it did...

THe gear is not Bending.....It is flexing....so that the wheel pants, back part, is contacting the ground...
In my case, pavement....

I believe the FOAM tires don't help much in this area either!....

Funny....because I have seen great planes cheapen there harware the boxes from time to time.

Ex....Earlier version of a 1/3 cap580 had very nice Robart wheels.....
year later, I had new kit, and it came with heavy NO Name wheels...

What type of wheels came with your Chipmunk??


I have only had the chance to take this plane to the field 1-time, so I can't know exatly about the landings untill I get the plane up in the air again...

Don't get me wrong, I greased some really NICE landings, it just seems like I am coming in WAYY more faster than needed...

I land on the mains, and it finally slows at the end of runway, and drops tail...

I thought I read some, loosing there plane due to "snapping" on final??

zdsh13

I'm pretty sure they are foam, I'll check when I get home.


The best thing you can do on any first flight is to check the low speed handling once you are satisfied with the flight trim. Try a couple slow passes at a safe height and see what the stalls are like... does it drop a wing tip or just drop a nose... Then try some lower passes at the lower speed to get a feel for the model at slow speeds.

Mine has really food low speed charactoristics, with flaps the approach is very predictable and lands at a nice speed... virtually 3 point every time. I also have my CG 1/4" further aft of the rear limit and it handles nice with no snap tendacies. If you have your CG closer to the forward limit you will have a harder time slowing the plane down for landings.

PlaneKrazee

My Feedback: (14)

Howdy boys!

Anyone working on or fly this plane? I'm about to take #3 out of the box to get it ready for spring.

kochj

I may have too much forward cg....
I will checC when spring retruns.... (a letter quit on my Ceyboard)

kochj

whats up...
I am thinking about converting my Gemini to gas...(already has the ignition)
Tired of the mess, constant adjusting, and siphoning..

I think My rudder may be leaning just a bit....
like the another said "nothing to bad" shouldn't effect flight much...

I have a NIB fuse, but will keep than untill I where out this one...

Cheers..

zdsh13

I just ordered a couple rcxel ignitions for my Saito's (FA-300T / FA-220). I'm still planning to run 5% nitro though, apparently the fuel efficiency is increased which results in alot less mess.... I've talked to a couple people who have completed similar conversions and they swear by it, less mess, easy starting, and better power. I guess I'll see....

kochj

The ignitions are great...even when using methanol & nitro..
I noticed a difference in sound (less fuel needed) The change could only be described as "less wet sounding"
I know that guys running the YS170's that had the ones with CDI...Were very forthcoming, that it indeed need less fuel, and made about the same, or slightly more power (mainly in the throttle responce)...

I personally haven’t noticed much difference in the "mess" but I believe that is due to the carb and it's loading up behavior (having the tank so high relative to the carb, exacerbates the siphoning)
I want gas on this one, nervous about the loss in power though...
I think it is at the lower end on this plane already...
It is aerobatic...right? not a trainer?? LOL...