TF FW190 GIANT ARF
11-01-2019, 03:31 PM
#4652
When you look at the top of the wing, gear down, tail on the ground (then tail raised level) you will notice where the axle is relative to the leading edge of the wing. The best position for the axle is to be well forward of the LE when the tail in down and at least even with the LE when the tail is up. This keeps the mass of the plane behind the axle as much as possible to help make it stable. As the axle position moves back the condition gets worse and all the typical problems get worse, nosing over, erratic veering, etc.
Look from the top the side views to get measurements and impressions on what's going on.
Adding a spacer to the back edge of the retract works but pay attention to the retracted position of the wheel too. The struts are like a foot long so a small washer under each screw is a good start then add two and see how it goes.
I usually set the gear/wheel at least parallel to the center line of the plane and then see how much deflection or twist there is in the strut. If the strut it tight then I add more toe out. If the strut is loose then I leave it because the torque of the wheel on the axle and lower leg will be enough of a toe out angle. You're looking at the scissor link for this info.
Also, it should be considered to replace the springs in the Robostruts with softer springs or a dual rate spring. They are made with very stiff springs! Its better to have a dual stage set up common on Yellow AC retracts. Ive made this mod to my planes many times and its so much better than stock.
Look from the top the side views to get measurements and impressions on what's going on.
Adding a spacer to the back edge of the retract works but pay attention to the retracted position of the wheel too. The struts are like a foot long so a small washer under each screw is a good start then add two and see how it goes.
I usually set the gear/wheel at least parallel to the center line of the plane and then see how much deflection or twist there is in the strut. If the strut it tight then I add more toe out. If the strut is loose then I leave it because the torque of the wheel on the axle and lower leg will be enough of a toe out angle. You're looking at the scissor link for this info.
Also, it should be considered to replace the springs in the Robostruts with softer springs or a dual rate spring. They are made with very stiff springs! Its better to have a dual stage set up common on Yellow AC retracts. Ive made this mod to my planes many times and its so much better than stock.
11-01-2019, 04:41 PM
#4653
My Feedback: (12)
Join Date: Dec 2001
Location: Jacksonville,
IL
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Will take all suggestions into consideration
I appreciate all that has replied
Hopefully we have a few flying days left this year in the Midwest
again Thanks and I will try to report back on my results
Roger
I appreciate all that has replied
Hopefully we have a few flying days left this year in the Midwest
again Thanks and I will try to report back on my results
Roger
11-04-2019, 06:19 AM
#4656
My Feedback: (9)
When you look at the top of the wing, gear down, tail on the ground (then tail raised level) you will notice where the axle is relative to the leading edge of the wing. The best position for the axle is to be well forward of the LE when the tail in down and at least even with the LE when the tail is up. This keeps the mass of the plane behind the axle as much as possible to help make it stable. As the axle position moves back the condition gets worse and all the typical problems get worse, nosing over, erratic veering, etc.
Look from the top the side views to get measurements and impressions on what's going on.
Adding a spacer to the back edge of the retract works but pay attention to the retracted position of the wheel too. The struts are like a foot long so a small washer under each screw is a good start then add two and see how it goes.
I usually set the gear/wheel at least parallel to the center line of the plane and then see how much deflection or twist there is in the strut. If the strut it tight then I add more toe out. If the strut is loose then I leave it because the torque of the wheel on the axle and lower leg will be enough of a toe out angle. You're looking at the scissor link for this info.
Also, it should be considered to replace the springs in the Robostruts with softer springs or a dual rate spring. They are made with very stiff springs! Its better to have a dual stage set up common on Yellow AC retracts. Ive made this mod to my planes many times and its so much better than stock.
Look from the top the side views to get measurements and impressions on what's going on.
Adding a spacer to the back edge of the retract works but pay attention to the retracted position of the wheel too. The struts are like a foot long so a small washer under each screw is a good start then add two and see how it goes.
I usually set the gear/wheel at least parallel to the center line of the plane and then see how much deflection or twist there is in the strut. If the strut it tight then I add more toe out. If the strut is loose then I leave it because the torque of the wheel on the axle and lower leg will be enough of a toe out angle. You're looking at the scissor link for this info.
Also, it should be considered to replace the springs in the Robostruts with softer springs or a dual rate spring. They are made with very stiff springs! Its better to have a dual stage set up common on Yellow AC retracts. Ive made this mod to my planes many times and its so much better than stock.
an easy test for the spring in the strut is with the plane sitting on it gear lift a wing tip a foot to 18in quickly (of coarse the tail wheel has to be in the air), while some one watches the strut on the ground for movement it should telescope in a bit with the movement. the strut should be sprung to the wt of the plane (2x the wt it, one strut, has to lift). but as a general rule if you bounce a landing you landed to slow, the springs are not dampened like on the man carrying planes so the wing has to be flying to dampen the springs. stall it on like in a 3 point landing can get ugly if it drops any distance to the runway..
Joe
Here 
11-05-2019, 05:01 PM
#4660
Yes, compared to scale drawings of the full scale plane the wheels are pretty much in the right location. Don't go any further forward.
Taxiing was improved because you increased the wheelbase between the tail wheel and main wheels. Now the plane will be more stable and have better feedback. Try it out and see what you think!
Taxiing was improved because you increased the wheelbase between the tail wheel and main wheels. Now the plane will be more stable and have better feedback. Try it out and see what you think!
11-06-2019, 08:50 AM
#4663
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Thanks Joe
after going through all of this I VAGUELY REMBER my old one may have had washers under the gear, hence why I never fad that problem with it
All good and ready for some better days
Thanks to all the gave suggestions
after going through all of this I VAGUELY REMBER my old one may have had washers under the gear, hence why I never fad that problem with it
All good and ready for some better days
Thanks to all the gave suggestions
02-18-2020, 05:48 AM
#4665
I bit the bullet, late as usual. Got me this bird, a Saito FG90R3 and a nice Keleo exhaust. Will probably get to at least try a Falcon 3 blade German Prop (23x10).
I'm still undecided at retracts. I really don't want to *******ize the mounts for Sierra, although they look so nice!! I read that folks are happy with the traditional air system by Robart, and some not so happy with the electric version??
Tailwheel I will likely do mechanical just so that I can do the scale like half-action.
Anything else I should keep an eye for? I think nose weight will not be an issue on this one. That 90R3 is HEAVY!
Where can I find a suitable three blade spinner? I can only find a Ziroli 4.5" (as close as it gets so far). I assume the Top RC would be too large, though it fits my Saito alright.
Thanks,
David
I'm still undecided at retracts. I really don't want to *******ize the mounts for Sierra, although they look so nice!! I read that folks are happy with the traditional air system by Robart, and some not so happy with the electric version??
Tailwheel I will likely do mechanical just so that I can do the scale like half-action.
Anything else I should keep an eye for? I think nose weight will not be an issue on this one. That 90R3 is HEAVY!
Where can I find a suitable three blade spinner? I can only find a Ziroli 4.5" (as close as it gets so far). I assume the Top RC would be too large, though it fits my Saito alright.
Thanks,
David
02-18-2020, 09:20 PM
#4666
David, according to this link the TOPA1882 3 blade spinner is in stock.
https://www.ogxphvbddesign.xyz/top-f...tem-49637.html
https://www.ogxphvbddesign.xyz/top-f...tem-49637.html
02-19-2020, 06:19 PM
#4667
David, according to this link the TOPA1882 3 blade spinner is in stock.
https://www.ogxphvbddesign.xyz/top-f...tem-49637.html
https://www.ogxphvbddesign.xyz/top-f...tem-49637.html
02-25-2020, 07:00 AM
#4670
My Feedback: (9)
the only reason I don't have one of these fockewulfs is because our club had a guy like me who only flies warbirds and he had a flop tite p-47 that had air Robarts in it with a shorter strut that the fockewulf and he would come out and fly it till the retract would not work correctly. then put it up till parts came in and do it again.the problems he was having were the structure of the retract would bend with each landing, and his landings were perfect.
im an ME and the design is not optimal, by a long shot! I looked very hard at buying the kit and moding it to fit std retracts, but correcting other engineers mistakes is a terrible way to start!
just my opinion
Joe
im an ME and the design is not optimal, by a long shot! I looked very hard at buying the kit and moding it to fit std retracts, but correcting other engineers mistakes is a terrible way to start!
just my opinion
Joe
02-25-2020, 11:02 AM
#4671
I still have this plane sitting new in box. Have the Sierra 1/5th fw190 retracts too... .
Just haven't gotten around to it. The amount of mod work is of course doable, but, time consuming.
That said, the example ive seen flying at our club flies nice, but the robart retracts are not very strong. Either electric or air(electric having more problems).
I've seen the gear bend on just the slightest touch down.
Either put in Sierra's or buy a TopRC and fit Sierra's from the get go.
Just haven't gotten around to it. The amount of mod work is of course doable, but, time consuming.
That said, the example ive seen flying at our club flies nice, but the robart retracts are not very strong. Either electric or air(electric having more problems).
I've seen the gear bend on just the slightest touch down.
Either put in Sierra's or buy a TopRC and fit Sierra's from the get go.
02-25-2020, 12:37 PM
#4672
My Feedback: (9)
I still have this plane sitting new in box. Have the Sierra 1/5th fw190 retracts too... .
Just haven't gotten around to it. The amount of mod work is of course doable, but, time consuming.
That said, the example ive seen flying at our club flies nice, but the robart retracts are not very strong. Either electric or air(electric having more problems).
I've seen the gear bend on just the slightest touch down.
Either put in Sierra's or buy a TopRC and fit Sierra's from the get go.
Just haven't gotten around to it. The amount of mod work is of course doable, but, time consuming.
That said, the example ive seen flying at our club flies nice, but the robart retracts are not very strong. Either electric or air(electric having more problems).
I've seen the gear bend on just the slightest touch down.
Either put in Sierra's or buy a TopRC and fit Sierra's from the get go.
joe
02-28-2020, 06:10 AM
#4673
If you look back farther in this thread you'll see a lot of discussion about the Robart retracts. Much of the problem was due to an issue where the trunion pins on the retracts were too soft, and would bend easily. A couple years ago Robart started hardening the pins, and since then they are much stronger. Even so, because of the length of the struts there is a lot of leverage when the plane ground loops, and you could damage the gear if it bounces, or rip out the mounts unless they have been improved over stock. Ground handling on grass is much more manageable than fabric or hard surface runways. Spacing the gear ahead is helpful to prevent nose over, but I've never found it to help much for ground looping. The only thing that helps somewhat is to have a bit of toe out to prevent the gear from tucking under (toe out is specified even in the full size 190 manual).
The Sierra modification is a great option, if you want the strongest possible gear. Keep in mind that to do it correctly you should increase the dihedral in the wing. The angles are set for a stock dihedral like on the SisT 190, and the wheels will be angled in if you don't make the change.
The Sierra modification is a great option, if you want the strongest possible gear. Keep in mind that to do it correctly you should increase the dihedral in the wing. The angles are set for a stock dihedral like on the SisT 190, and the wheels will be angled in if you don't make the change.
06-07-2020, 12:46 PM
#4674
Unfortunately I had a switch failure that caused me to loose my glassed 190. I had a lot of good flights on it, and had it dialed in and running great with the EME-70 Twin. At least the retracts came away with no damage, so I'll have a well used but perfectly functional set of 1:5 scale Sierra Giant Scale 190 retracts with wheels to sell. I be putting them on the Buy & Sell soon.
