CARF-Models P-47 Thunderbolt
05-31-2014, 11:35 PM
#576
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Here are a couple of emails Ian Howard from DA in Australia forwarded on to me from Andreas (CARF):
Only two planes were made with the assymmetric linkage. Unfortunately right the one which was used for the manual. You have to use two rudder pins. One from the top, one from the bottom. I have this on my prototype, but I didn't like the fact that the bottom pin could possibly fall out unnoticed, causing issues with the rudder pull pull cables, creating play and flutter. So I came up with the "ingenious" idea to put the elevator linkage to the side... So we made two planes like that, until we realized that it causes problems with the rudder cutout in this area, looking a bit odd because you can see the linkage from one side. It just didn't seem right. So we changed back. It is important to secure the bottom pin thoroughly. Most likely it will never have to be removed, so it could be glued with Epoxy.
Regards,
Andreas
You can limit aileron to 15-20 mm with a good expo. that's why the shortest possible servo arm must be used. 12 mm is enough. The aileron control horn is only 23-24 mm and you should use at least 70-80% of the standard servo throw. You should definitely program a 15-20% opposite mix from rudder to aileron, as stated in the manual. You do need the rudder throw, though.
The rudder has a very high roll coupling. It becomes even evident on the ground during takeoff. So, a rudder correction on the ground, will act as aileron as soon as the plane lifted off, which can result in bad situatios. That's why I mix 20% opposite aileron to the rudder, which compensates this behavior. Fine tuning can be done with 4 point rolls, where you can see if the 20% is correct or needs to be decreased or increased a bit.
Most important is the CG. Do not attempt to fly the plane with a CG further back than in the manual! The plane seems to feel light on the tail wheel when taxiing. No choice, that's what it is. Need to be a bit careful and hold elevator when taxiing on grass fields. Also during take off, Hold elevator until the plane gains a little speed. Don't take off with full power. Lift off with half throttle, get the gear up and then throttle up.
You also will have to play with a right rudder mix, to compensate for the little right thrust in the motor installation. You can't put the correct right thrust because firstly, it would look awkward, secondly, you can't put the engine enough out of center to keep it under the cowl. So, it needs to be compromised with a 1-2% right rudder mix at full throttle. The nose heavier the plane, the smaller this effect.
Don't land with the engine at full idle. Always keep 1-2 klicks of throttle and take the throttle all the way back ONLY when the tailwheel is on the ground. You won't be able to stear the plane on the ground, as a very low idle will let the airflow around the rudder and stab collapse. As long as you keep 2 clicks of throttle, the prop lets enough air through to have clean airflow on all controls.
Sorry if this sounds complicated, but you asked for it...
Best regards,
Andreas
Only two planes were made with the assymmetric linkage. Unfortunately right the one which was used for the manual. You have to use two rudder pins. One from the top, one from the bottom. I have this on my prototype, but I didn't like the fact that the bottom pin could possibly fall out unnoticed, causing issues with the rudder pull pull cables, creating play and flutter. So I came up with the "ingenious" idea to put the elevator linkage to the side... So we made two planes like that, until we realized that it causes problems with the rudder cutout in this area, looking a bit odd because you can see the linkage from one side. It just didn't seem right. So we changed back. It is important to secure the bottom pin thoroughly. Most likely it will never have to be removed, so it could be glued with Epoxy.
Regards,
Andreas
You can limit aileron to 15-20 mm with a good expo. that's why the shortest possible servo arm must be used. 12 mm is enough. The aileron control horn is only 23-24 mm and you should use at least 70-80% of the standard servo throw. You should definitely program a 15-20% opposite mix from rudder to aileron, as stated in the manual. You do need the rudder throw, though.
The rudder has a very high roll coupling. It becomes even evident on the ground during takeoff. So, a rudder correction on the ground, will act as aileron as soon as the plane lifted off, which can result in bad situatios. That's why I mix 20% opposite aileron to the rudder, which compensates this behavior. Fine tuning can be done with 4 point rolls, where you can see if the 20% is correct or needs to be decreased or increased a bit.
Most important is the CG. Do not attempt to fly the plane with a CG further back than in the manual! The plane seems to feel light on the tail wheel when taxiing. No choice, that's what it is. Need to be a bit careful and hold elevator when taxiing on grass fields. Also during take off, Hold elevator until the plane gains a little speed. Don't take off with full power. Lift off with half throttle, get the gear up and then throttle up.
You also will have to play with a right rudder mix, to compensate for the little right thrust in the motor installation. You can't put the correct right thrust because firstly, it would look awkward, secondly, you can't put the engine enough out of center to keep it under the cowl. So, it needs to be compromised with a 1-2% right rudder mix at full throttle. The nose heavier the plane, the smaller this effect.
Don't land with the engine at full idle. Always keep 1-2 klicks of throttle and take the throttle all the way back ONLY when the tailwheel is on the ground. You won't be able to stear the plane on the ground, as a very low idle will let the airflow around the rudder and stab collapse. As long as you keep 2 clicks of throttle, the prop lets enough air through to have clean airflow on all controls.
Sorry if this sounds complicated, but you asked for it...
Best regards,
Andreas
06-02-2014, 02:18 AM
#577
Comp ARF P47.
Note the elevator system is pre-assembled at the Comp ARF factory. The parts are secured with Hysol and the manual only requires the builder to apply a drop of permanent thread lock to secure the ball links retention nut.
As Greg has stated, this is a defiant preflight/post flight item.
IMO, this is an inferior design and needs upgrading!
Here is a very simple fix using a Hangar Nine Ball link system.
I have this kit : http://www.hangar-9.com/Products/Def...ProdID=HAN3615
But I think these black supporters was great. Where can I find a kit like yours?
Thanks
Alf
06-02-2014, 02:22 PM
#578
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Hardware is defiantly Hangar Nine stuff, it maybe hard to find so this may work for you as well:
First make sure you use the brass collar, carbon fiber will shatter, and the following process does enlarge the hole somewhat.
Find a very large collar (something like a wheel collar). Drill the center hole as to slide over the brass collar. Next drill the hole for the rod that is going to connect to your elevator. (Note this is center point drill and may take a few tries.) Make thin cut through one side of the assembly. This is needed to provide crush space and allow for some clamping force. Use Hysol and thread lock to lock it all in place.
Hope this makes sense to you, if not I will post a photo or something....
Phil
First make sure you use the brass collar, carbon fiber will shatter, and the following process does enlarge the hole somewhat.
Find a very large collar (something like a wheel collar). Drill the center hole as to slide over the brass collar. Next drill the hole for the rod that is going to connect to your elevator. (Note this is center point drill and may take a few tries.) Make thin cut through one side of the assembly. This is needed to provide crush space and allow for some clamping force. Use Hysol and thread lock to lock it all in place.
Hope this makes sense to you, if not I will post a photo or something....
Phil
06-04-2014, 05:08 PM
#579
Gents, I fear that too many are over-thinking all of this. With a single elevator servo (Hitec 5955TG), robust linkages, and NO mixes of any kind, the P-47 flies wonderfullly, lands and takes off very predictably. This is an HONEST airplane with few bad habits. It flies very scale as set up in the manual with a Moki 250 and the 4 blade prop, and should last for a LONG time as long as regular maintenance is performed and we all avoid "dumb thumbs." There is no harm in being overly cautious or over-engineering, but those considering this plane and reading this thread for guidance should understand that the airplane and the manual are THOROUGHLY tested. The ONLY area I would modify is my suggestion to use copper water heater tubing for the exhaust extensions. UNLESS the builder can braze or utilize a very high content Silver solder, joints will NOT hold up to the heat generated by the Moki. Vogelsang sells the appropriate exhaust extension tubing, which IS what I ended up using on my airplane. However, brazing or at least 50% silver solder could have made my suggestion viable. Otherwise, this airplane ROCKS!!!
06-04-2014, 08:15 PM
#580
Very good and accurate post Richard. I agree that the design is more than adequate. I also do think that any issues that have come up in flight with the elevator ball linkage, probably do actually originate with loose bolt holes (into elevator halves through carbon rod. Its easy to wear out carbon if cross threading and over tightening. Any flutter/movement there could work the control rod linkage to the point of fatigue induced failure. This joint HAS to be tight with no play. If needed, wick some CA, and re-tap.
Voy
Voy
06-04-2014, 08:35 PM
#581
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Richard
I have build many Comp ARF aircraft over the years. Most recently their Corsair's with folding wing and two P47's, each time I have followed the instructions for the most part. Comp ARF are top in their class, however with that being said I have personally witnessed this elevator begin to fail with less than 7 flights. It is weak and poorly designed, given the value and size of this model it has for all practical purposes a 60cc class hard in this area. Elsewhere, this model is among their best and superior to the Corsair...
Please keep a close eye on this area, good luck. Its a great plane...
Phil
Note; On this particular P47 the two elevators half's maintained a good lock. No flutter was encountered as the fault was detected early before too much slop developed...
I have build many Comp ARF aircraft over the years. Most recently their Corsair's with folding wing and two P47's, each time I have followed the instructions for the most part. Comp ARF are top in their class, however with that being said I have personally witnessed this elevator begin to fail with less than 7 flights. It is weak and poorly designed, given the value and size of this model it has for all practical purposes a 60cc class hard in this area. Elsewhere, this model is among their best and superior to the Corsair...
Please keep a close eye on this area, good luck. Its a great plane...
Phil
Note; On this particular P47 the two elevators half's maintained a good lock. No flutter was encountered as the fault was detected early before too much slop developed...
Last edited by JustJets; 06-04-2014 at 08:38 PM.
07-10-2014, 06:10 AM
#585
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Join Date: Mar 2002
Location: sao paulosao paulo, BRAZIL
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hello fellow builders!
i have just started a razorback and just read carefully the whole threat, congratulations! the manual is by far the best from C-arf (congrats Richard!) and i just finished the MIG 15 (with a poor manual, but better thant the A4 wich have no manual at all!).
any advice to purchase extra items to dress the model?
so far i have seen here:
DBA cockpit
new spinner
tailormade declas
what else do we have?
i would like to have some more items like lights, lenses, wing ordinance, pilot.....
will start adding pictures soon!
best regards from Brazil
Fred
i have just started a razorback and just read carefully the whole threat, congratulations! the manual is by far the best from C-arf (congrats Richard!) and i just finished the MIG 15 (with a poor manual, but better thant the A4 wich have no manual at all!).
any advice to purchase extra items to dress the model?
so far i have seen here:
DBA cockpit
new spinner
tailormade declas
what else do we have?
i would like to have some more items like lights, lenses, wing ordinance, pilot.....
will start adding pictures soon!
best regards from Brazil
Fred
07-10-2014, 06:25 AM
#586
If you haven't already ordered your cockpit kit. Iflytaillies makes an amazing kit. Spendy, but if the time/money ratio goes in your favor to the latter, they are awesome. I have the corsair and wulf versions, stunning detail.
http://www.iflytailies.com/store/ins...cale-warbirds/
I bought the drop tanks from CARF. Then I bought a ton of books on the P-47. The drop tanks they sell were very rarely used on the 47! Kinda bummed. I ordered the 500pound bombs as well.
Are you putting a moki in it? If you are, I can send you a template for the baffle, save you a bunch of time!
I put the formation lights on my corsair. Gary Prince sells a kit for the corsair, it is probably close to same size for the 47. I saw the indentations on the wing, next time I have it out of the bag, I'll check the size.
http://www.iflytailies.com/store/ins...cale-warbirds/
I bought the drop tanks from CARF. Then I bought a ton of books on the P-47. The drop tanks they sell were very rarely used on the 47! Kinda bummed. I ordered the 500pound bombs as well.
Are you putting a moki in it? If you are, I can send you a template for the baffle, save you a bunch of time!
I put the formation lights on my corsair. Gary Prince sells a kit for the corsair, it is probably close to same size for the 47. I saw the indentations on the wing, next time I have it out of the bag, I'll check the size.
07-11-2014, 09:10 AM
#588
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Helllo Dr! thanks a lot for the information, i am sure my client will go with the Iflytaillies cockpit! and yes, we´re gonna hang a Moki on her nose!
thanks for the template offering, will save a lot of time indeed! will measure the wing indentations and be back to you
so bad to hear about the tank from C-arf. i am still waiting to know wich version owner will choose to...
next week i´ll have more news, right now i am still finishing the C-arf Mig 15 and just started to leard more about this bird
best
Fred
thanks for the template offering, will save a lot of time indeed! will measure the wing indentations and be back to you
so bad to hear about the tank from C-arf. i am still waiting to know wich version owner will choose to...
next week i´ll have more news, right now i am still finishing the C-arf Mig 15 and just started to leard more about this bird
best
Fred
07-25-2014, 02:59 AM
#589
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i have made some progress wich means a lot on this so easy to build bird!
main landing gear already installed
one side needed to sand the shims, on the other it was just a drop-in and bolt.
air ram for the doors are not Robart, so support that came with model was useless, made a longer one from scrap
i have noticed that hinge gap line is absolutely unscale, and for this size model looks really odd. i plan to make some imporvements there so you cannot see through the hinge line as actually you can do it now.
have contacted details 4 scale and found that they have a full lights kit for the P-47, just ordered!
and will work on the cowl flaps, pictures soon!
main landing gear already installed
one side needed to sand the shims, on the other it was just a drop-in and bolt.
air ram for the doors are not Robart, so support that came with model was useless, made a longer one from scrap
i have noticed that hinge gap line is absolutely unscale, and for this size model looks really odd. i plan to make some imporvements there so you cannot see through the hinge line as actually you can do it now.
have contacted details 4 scale and found that they have a full lights kit for the P-47, just ordered!
and will work on the cowl flaps, pictures soon!
10-08-2014, 02:47 AM
#591
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Hi
I'm looking into one of these birds, they are stunning.
How long are they, prop to tail? I can't find that in the manual, it's kind of important to see if it will fit in my hangar!
Thanks
I'm looking into one of these birds, they are stunning.
How long are they, prop to tail? I can't find that in the manual, it's kind of important to see if it will fit in my hangar!
Thanks
10-08-2014, 03:23 AM
#592
hack_1979,
[TABLE="width: 100%"]
[TR]
[TD]
Wingspan[/TD]
[TD] 110" (2800 mm)[/TD]
[/TR]
[TR]
[TD]
Length[/TD]
[TD] 90" (2300mm)[/TD]
[/TR]
[TR]
[TD]
Weight[/TD]
[TD] 48 - 53 Lbs (22 - 24 kg) dry[/TD]
[/TR]
[TR]
[TD]
[/TD]
[TD] 80 - 150 ccm 2 stroke / 250 ccm 4 stroke radial[/TD]
[/TR]
[TR]
[TD]
[/TD]
[TD] 8-10 middle to high class servos[/TD]
[/TR]
[/TABLE]
[TABLE="width: 100%"]
[TR]
[TD]
Wingspan[/TD][TD] 110" (2800 mm)[/TD]
[/TR]
[TR]
[TD]
Length[/TD][TD] 90" (2300mm)[/TD]
[/TR]
[TR]
[TD]
Weight[/TD][TD] 48 - 53 Lbs (22 - 24 kg) dry[/TD]
[/TR]
[TR]
[TD]
[/TD][TD] 80 - 150 ccm 2 stroke / 250 ccm 4 stroke radial[/TD]
[/TR]
[TR]
[TD]
[/TD][TD] 8-10 middle to high class servos[/TD]
[/TR]
[/TABLE]
Last edited by Greg Wright; 11-22-2014 at 04:22 PM.
01-04-2015, 10:13 AM
#596
Join Date: Dec 2011
Location: burlingtonontario, CANADA
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Gear doors finished. Didn't like the bent wire look so made up some brackets to hold things together.
Pumped Hysol between the inner and outer skins through the mounting holes of the doors to provide a solid section for the screws to pass through.
Pumped Hysol between the inner and outer skins through the mounting holes of the doors to provide a solid section for the screws to pass through.
Last edited by peter w h; 01-04-2015 at 10:17 AM.