c.g. balancing 1400mm corsair

[bagger]

RE: c.g. balancing 1400mm corsair

As soon as I maiden it I will post my reviews. When I had the battery under the canopy and in the battery tray I made, I balanced it at 110mm too. It flew good until a cross-wind caught me. Time for a new Corsair. Thanks for your input Charlie. Will post soon.

bagger

[bagger]

RE: c.g. balancing 1400mm corsair

Maiden the FMS Corsair today with the c.g. at 110mm. As seen in the picture I posted, at balancing, it was a little nose heavy. Had a NW wind today at 12 mph with an occasional little gust. Our runway runs N to S. With the weight in the tail it still came up pretty easy. Ground control was much better on this set up. Got the plane up in the air and had to use all my elevator trim to get it leveled out. Trimmed out everything else and flew it for 3 minutes. Upon landing with flaps, it was nose heavy. Had to keep pulling elevator back to keep nose up. Landed it and it nosed over. No damage.

Before the second flight I checked where the elevator was set at and re-adjusted so I could have trim again. Much better the second time. Had to trim the elevator very little and it was much easier to control. Didn't have to pull back on the stick so much. Flew for 4 minutes, dropped gear and flaps and made my approach about half throttle. By the end of the runway I lowered the throttle to about 30% and them pretty much cut the power. It sailed in nicely and I had a gentle landing.

I like the way this one flies better than the one I replaced. I think using the battery compartment is much better. Why the 2 weights in the nose is still a mystery to me. They are not needed there. You need them in the back. I filmed both flights so I can go back and see how the changes I made between the 2 flights helped.

I hope these threads help anyone who purchases this plane. It is fun to fly and I thought was very manageable on the ground and in the air. Good luck all!

bagger

[ryramZ]

RE: c.g. balancing 1400mm corsair

Maiden the FMS Corsair today with the c.g. at 110mm.  As seen in the picture I posted, at balancing, it was a little nose heavy.  Had a NW wind today at 12 mph with an occasional little gust.  Our runway runs N to S.  With the weight in the tail it still came up pretty easy.  Ground control was much better on this set up.  Got the plane up in the air and had to use all my elevator trim to get it leveled out.  Trimmed out everything else and flew it for 3 minutes.  Upon landing with flaps, it was nose heavy.  Had to keep pulling elevator back to keep nose up.  Landed it and it nosed over.  No damage.

Before the second flight I checked where the elevator was set at and re-adjusted so I could have trim again.  Much better the second time.  Had to trim the elevator very little and it was much easier to control.  Didn't have to pull back on the stick so much.  Flew for 4 minutes, dropped gear and flaps and made my approach about half throttle.  By the end of the runway I lowered the throttle to about 30% and them pretty much cut the power.  It sailed in nicely and I had a gentle landing.

I like the way this one flies better than the one I replaced.  I think using the battery compartment is much better.  Why the 2 weights in the nose is still a mystery to me.  They are not needed there.  You need them in the back.  I filmed both flights so I can go back and see how the changes I made between the 2 flights helped.

I hope these threads help anyone who purchases this plane.  It is fun to fly and I thought was very manageable on the ground and in the air.  Good luck all!

bagger

what battery?

[bagger]

RE: c.g. balancing 1400mm corsair

I'm running an Admiral 4s 14.8v 3000mAh 30c. Only weight in the front of the plane is the battery and ESC, motor and prop.

[OV10]

RE: c.g. balancing 1400mm corsair

Hello bagger,

Ever since your maiden report with the CG set at 110mm with those 2 ounces of mystery weight from the cowl relocated to the tail I have held off flying mine anymore until I made some time to investigate. Well after a good 10hrs at the field today with my 1400 size P40 and P39 I decided that I was going to get into the F4U when I got back home this evening. Well..........I am totally baffled as to where those cowl weights are!!!
Here's my bird balancing at 90mm (4000 4S in the batt pocket and no additional weight) as the forums suggested but it flies really heavy and hot because of it. That is why I became so curious to your discovery.

Here it is with cowl removed....... can not find those weights you have been talking about.


Where did you find those weights in relationship to what my photo shows? Behind the motor buried in the foam?? I am going bonkers looking behind the motor with inspection mirrors to no avail. ARRRGGGG
Appreciate some insight

Best Regards,

[bagger]

RE: c.g. balancing 1400mm corsair

Charlie,

On your bottom picture where the rectangular hole is under the motor I had 2 spaces, one on each side. That's where I found my weights. There were hot glued in place. That was in the RTF fuselage. When I got my replacement fuselage, there were no weights in those holes and I didn't put them back in there. I relocated them to the back.

How old is your 1400mm Corsair? My old one I crashed was 2 years old. It was old enough that it came the plastic landing gear instead of the new metal gear version. It DID NOT have the weights in it. My new RTF Corsair I bought about a month ago had the weights in it. Maybe it's something that was done on the newer version with the new metal gear to comprehend for the added weight of the gear? I don't know.

I hope you didn't have to destroy your cowling to get it off. Mine was glued on so good I had to tear it off in pieces. That's why I had to replace it too. Don't know what else I can add right now to help you. Please keep me posted on your progress. I'm curious as well as to why the weights were there myself and why you can't find or you don't have any. If they are there, you should be able to see them. Good luck.

bagger

[OV10]

RE: c.g. balancing 1400mm corsair

Hello bagger,
Mine is the latest v3 which I got this past Xmas. I only took off the $8 plastic cowl. The pic with the hole under the motor is the $14.50 foam cowl which I left in place because I would have to destroy it to get it off. So it appears from what you just described your old foam cowl had the weights and the new foam cowl that you have now is v3(which I have too) don't have the weights. It all becomes pretty clear to me now based on your remaiden results that the forum group recommendations for a CG of 90-95 was probably based on the old cowl weights and that the 110 is now more accurate reflecting the factory removal of the weights. Mine requires about 10% up trim to offset that nose loading which shows in my pic 1 (post#25) of it balancing at 90mm.
So it looks like my options to reduce it's heavy nose is too start moving the battery aft which will probably require a custom tray(could use the newer P51 battery tray) or install weight in the tail as you did with the relocation of the ones you removed from the earlier version cowl. So now my only question for you that remains in order to make a decision on what mod plan to use is how much did those weights you transplanted weigh out at(hopefully you measured them).
Thanx,

[bagger]

RE: c.g. balancing 1400mm corsair

Charlie,

Looking now at the front of your plane, I see you only took off the plastic trim of the cowl. You have to take off the whole foam cowl. There should be 2 slots, one on each side. If you have weights, that's where they'll be. That's what I meant about destroying my cowling. They are behind that. Motor has to come off and be disconnected and then the cowling. Not a pleasant thought, I know. That's where my weights were.

The new plane, which I bought a month ago, had the weights there. The old one didn't. The old one was advertised as a V3. Motion website showed the new metal retracts so I upgraded to them. And they made a positive difference. So positive I bought an extra set and put them on my FMS 1400mm P-40. I getting off track now.

Anyway, the whole foam cowling has to come off to access those weights. Keep me posted on your decision. Good luck.

bagger

[boomer108]

RE: c.g. balancing 1400mm corsair

Hello Warbird and Bagger,

I also have the  V3 and to set the record straight,in post #6 I mistakenly said I balanced with the gear extended. I balance inverted gear up using a Turnigy 3000 30c 4 cell. I found no weights in the cowl but I do do have 1 ounce of weight added to the tail. My question to Warbird is where do you set your cg machine pads on your wing?

Roy B.

[OV10]

RE: c.g. balancing 1400mm corsair

bagger,
Ooops, you told me that the old one didn't have weights and the new one did in your post 26 and I said just the opposite(I'm a dumbass) in my analogy. Thanx for restating to getting my thinking straight. Now the real burr under the saddle is the fact that it looks like the foam cowl would have to require MAJOR surgery(destroy it) in order to find and relocate those hidden weights and I am not going to do that at this point. I'd rather go for a battery tray relocated aft mod to make the 100-110 CG range. You didn't mention any adverse pitchiness on the remaiden at the 110 CG which is good. You mentioned using all of your elevator up(pull back) trim which indicates it was still heavy to the front but a lot less than before which is the whole point to this discussion.
Lastly, I put the v3 Corsair retracts on my 1400 P-40 also with just a minor mod in added length. Thanx for sharing your findings.

boomer,
Am using a Great Planes CG fixture too, however I do have a connecting rod that is twice the length of the originals to spread the stands father apart which I use on larger birds. This Corsair kinda fell into that category because I wanted the pads to rest in the bend of the gull. The leading edge of the wing starts to sweep aft an inch outboard of this point. Rereading your post 6 I see that you are good with your bird at the 110 mark. So between both of your inputs I now have a CG mod mission in sight without having to do a lot of trial and error efforts to make this bird the fighter it should be.
ps - I got a sneaky suspicion that you've got weight buried in that foam cowl that you wont find unless you rip it off. Thanx for your inputs also.

Best Regards,  

[bagger]

RE: c.g. balancing 1400mm corsair

Don't blame you for not wanting to tear up the cowling. My first Corsair I made a battery tray and mounted it up against the backside of the firewall in the fuselage cavity. Was able to get the 110c.g. by shifting the battery. It flew well there. Good luck with the Corsair Charlie.

boomer,
Thanks for your input and good luck with your Corsair. I'll be looking for both you guys on this thread to see your results.

bagger

[boomer108]

RE: c.g. balancing 1400mm corsair

Hey Warbird!
I'm with you,I don't want to tear up the cowl looking for those magnets but I think I'm going to put a pencil magnet I have in that lower air opening and see if something sticks. Good flying Warbird.

Roy B.

[CaptRon]

RE: c.g. balancing 1400mm corsair

Greetings all.  Just purchased my 2nd 1400mm Corsair.  On my first one, I didn't use the battery compartment because I needed to add 4 ozs. of weight to the tail.  I made a tray and glued it right behind the compartment and was able to get the proper balance by moving the battery.

On this new Corsair I want to use the compartment.  Has anyone had trouble balancing this plane using this compartment?  I don't want to add weight to the tail or stick a tray in again.  Any help is appreciated.  Thanks.

Hey bagger,
I just got the 1400mm FMS Corsair.  I put the thing together and off I went to the field.  The Maiden flight went GREAT !!
While landing after the second flight she nosed over that was my fault.
So back to the bench I went and found that the COG was at 85 mm.   This is with a 3600 mah battery and the gear in the down position.
I don't really want to add weight to the tail because she flew so well.  I'm not sure what to do.
Do I leave well enough alone? or do I change the COG to match the manual?
[hr]

Greetings all.  Just purchased my 2nd 1400mm Corsair.  On my first one, I didn't use the battery compartment because I needed to add 4 ozs. of weight to the tail.  I made a tray and glued it right behind the compartment and was able to get the proper balance by moving the battery.

On this new Corsair I want to use the compartment.  Has anyone had trouble balancing this plane using this compartment?  I don't want to add weight to the tail or stick a tray in again.  Any help is appreciated.  Thanks.

Hey bagger,
I just got the 1400mm FMS Corsair.  I put the thing together and off I went to the field.  The Maiden flight went GREAT !!
While landing after the second flight she nosed over that was my fault.
So back to the bench I went and found that the COG was at 90 mm.   This is with a 3600 mah battery and the gear in the down position.
I don't really want to add weight to the tail because she flew so well.  I'm not sure what to do.
Do I leave well enough alone? or do I change the COG to match the manual?

[wrongroad]

RE: c.g. balancing 1400mm corsair

G'day gang,
If I may join the discussion here on the CG of the F4U Corsair.
The CG of 110mm is correct for the V2 unit and I have no drama flying the model at that. However, I have found that the nominated CG of 110mm is way off for the V3.
The first three flights I attempted with the CG at this were exciting to say the least with any change of direction meet with a savage snap.
I reset the CG to 95mm and found the machine to be a wonderful experience to fly. No more clenched butt cheeks to worry about :D
I only ever use the nominated CG point as a starting point. I then play with the Cg until I get a balance that suits me... not you ;) I am sure that if some of you were to ever fly my models you would be wondering how I fly them and some of you would say that is great to fly. What ever floats your boat or flies your plane :)
If you will indulge me here.
During the take off run, get the tail into the flying position as quickly as you possibly can. Watch any old footage of Corsairs taking off and you will note that the pilots rev up against the brakes and get the tail up ASAP. The reason is simple. The long landing gear put the wing at a high AoA and the model does have a habit of getting airborne before flying speed has been achieved. This usually results in a nice cartwheeling crash. Youtube is full of Corsairs crashing in just this manner.....a roll to the left, a wing tip touches the ground and the rest is history. The whole wing is stalled it is not a 'simple' tip stall.
I crashed a Corsair in just such a manner and I was reminded that I was NOT flying my Mustangs and that I should not keep the tail on the ground. The information came from non other than a Korean war Corsair pilot. So I listened.
You will also need to manage the rudder during the initial part of the take off run. Go to sleep and she will go left in a hurry. Ask me how I know this. Thankfully we had a cross strip at the right place.
I do not use full flap for landing as, via the same source of advice, it was pointed out to me that the flaps on the FMS unit are really too big for the weight of the model and full flap is like hanging out big barn doors. The flaps are producing drag not lift and that is the idea of stopping the full sized aircraft for landing on an aircraft carrier.
There is already a lot of drag with the frontal area of the gear doors hanging in the breeze.
I also dial in a bit of nose down so that I can have a positive rate of descent that I can control with the throttle and elevators.
The Corsair needs a fair amount of power on during the approach phase as speed is required if you are using flap. Once the flaps are used, you are taking away a large portion of the wing and therefore lift.
I fly off grass only and I do get the odd nose over but it is usually because of the top dressing that is still growing a full coverage of grass.
It is one thing that I have noticed in many reviews and that is the reviewer saying that the model will land at walking pace. I really wish that the reviewers would not say that as it invites pilots to slow down too much particularly with warbirds.
Regards and respect
Daryl

[OV10]

RE: c.g. balancing 1400mm corsair

Hello Wrongroad,

I welcomed you earlier on another Squawk thread but just wanted to reiterate that I am glad to have your contributions here so that I don't have to chase over to the RCG forum for info. I totally agree with your comment about manufacturer CG placement is a "starting" point. I like you am an experienced warbird pilot and also an airshow demonstrator so the rest of your commentary I align to also, especially your very last sentence.
So the main reason for my post is as a follow up to my postings last July on this thread whereas I was going to do a battery tray mod. Well the tray mod turned out awesome and was the ticket for holding the relative CG location around 95 and allowed me to use my 4000mAh 4S batts. Got pics for ya all now! 

Best regards,

[boomer108]

Hey Guys!

. Just revisiting this post to see if anyone has seen the new Horizon Hobby Staufenbiel Red Bull Corsair? It is the FMS 1400 V3 Corsair. So I guess that gives some credence to the rumor that FMS and Horizon Hobby are in bed together. What really got me
was the recommended cg is 95 with a recommended 2600 25c battery. I guess they must have removed those hidden weights in the NACA cowl.

Roy B.

[wrongroad]

G'day Roy,
You must keep in mind that the V2 and the V3 are completely different models. As different as trying to line up a T-28 with a FW190.
The V2 has the foam cowl and the V3 is fitted with a plastic cowl. The plastic cowl is quite weighty.
The V2 has the weights but I have not seen or been able to detect any in the V3.
The V2 is 2000 grams and the V3 is 2500.
So, you can see that there is a major difference in the way they are a manufactured.
The GC for the V2 is 110mm and this is good for that model but it was originally the nominated point for the V3 but this has now been corrected to 90/95mm.
Just do not make the mistake of trying to blend the two models together as one as they are not.
Regards and respect
Daryl

[boomer108]

Thanks WrongRoad!

. There's been so much discussion about the FMS Corsairs cg and everyone having a different approach to balancing it. I have the V3 and cg mine using a Turnigy 4s 3000 30c at 110 from the leading edge on my Great Planes balancer with 1 1/4 ounces of weight in the tail. I have always suspected that cg point to be wrong but haven't seen FMS change their manual. Mine flys fine, but I'm a stickler for correct info. That kind of info could make a inexperienced guys day real bad. Thanks again and good flying.

Roy B.

[Pheonix]

On the CG for the Corsair, I have an earlier version that states the CG is 90mm. This seems to work for me. Of course, I made some significant changes by upgrading the gears with the new P40-B gears and the new 680 Kv motor. The plane is really nose heavy now as I expected it would be. Using an Admiral 3600 50C battery, I had to add about 1 1/2 oz. of weight to the tail. I will fly this weekend and see how it goes.

[dkalwishky]

For you guys adding weight to the tail, can you post some pictures of how you did it and where you located the weight?