BBA/Winter Build 2017/18 - Top Flite Corsair
- Thread starter willsonman
- Start date
Very nice! Eagerly awaiting your first flight video.
Thanks fellas, I'm just as excited to get her in the air. I spent the weekend doing the family thing. As I'll be leaving Wednesday for SEFF, I felt my time would be best used with them before my departure.
I have just a couple of things I'd like to touch on before I go.
The main gear doors need some endpoint adjustment. The wheels do touch the doors during the retraction. They did not do that before I painted so it may be some residual primer that misted onto the push rods that is causing just a touch of binding. Not a big deal. The left front gear door was binding during retraction and subsequently the hinge for it broke free. I believe this binding is due to a slight design flaw in the 3D printed support. I did not bevel the leading edge of the hole. I'll sand this down as well as look at any residual paint on the oleo. I noticed this issue when I first installed the oleos after paint. The acrylic likes to stick to the ABS part. You can see, visually, what I mean by this bevel I should have modeled in the images below.
The other issue is the canopy slide. When I installed it I had completely free movement with three mounting points. After I put on the 4th mounting point (last one was at the rear) There was binding. I believe the issue is that the rear portion of the canopy makes contact with the fuselage and it sticks, preventing full closure and binds up when trying to retract. My mounting holes should be slightly lower to allow the rear portion of the canopy to sit higher and not make contact with the fuselage. This is a pretty simple fix so I hope to get it done quickly.
Last of all, I need a battery strap. As she sits a bit nose heavy I need to add some holes to the battery tray as well. No big deal there.
Other than that, she is all set for SEFF. Carl really was gracious enough to find this video of the same model flying at the same 13-pound weight...
It gives me confidence that she will fly but I want a nice long takeoff like this to make sure the air is making the wing fly before I ROG. On my home field I will likely need to use flaps for takeoff but not knowing if she needs a flap-elevator mix makes SEFF a great place for a first flight and do some shake down on her.
I have just a couple of things I'd like to touch on before I go.
The main gear doors need some endpoint adjustment. The wheels do touch the doors during the retraction. They did not do that before I painted so it may be some residual primer that misted onto the push rods that is causing just a touch of binding. Not a big deal. The left front gear door was binding during retraction and subsequently the hinge for it broke free. I believe this binding is due to a slight design flaw in the 3D printed support. I did not bevel the leading edge of the hole. I'll sand this down as well as look at any residual paint on the oleo. I noticed this issue when I first installed the oleos after paint. The acrylic likes to stick to the ABS part. You can see, visually, what I mean by this bevel I should have modeled in the images below.
The other issue is the canopy slide. When I installed it I had completely free movement with three mounting points. After I put on the 4th mounting point (last one was at the rear) There was binding. I believe the issue is that the rear portion of the canopy makes contact with the fuselage and it sticks, preventing full closure and binds up when trying to retract. My mounting holes should be slightly lower to allow the rear portion of the canopy to sit higher and not make contact with the fuselage. This is a pretty simple fix so I hope to get it done quickly.
Last of all, I need a battery strap. As she sits a bit nose heavy I need to add some holes to the battery tray as well. No big deal there.
Other than that, she is all set for SEFF. Carl really was gracious enough to find this video of the same model flying at the same 13-pound weight...
It gives me confidence that she will fly but I want a nice long takeoff like this to make sure the air is making the wing fly before I ROG. On my home field I will likely need to use flaps for takeoff but not knowing if she needs a flap-elevator mix makes SEFF a great place for a first flight and do some shake down on her.
Ok, so I took just an hour or so to sort things out last night.
The battery hatch had 8 3/4" holes drilled into it and I secured a heavy duty velcro strap to it with medium CA. It holds all three batteries nice and secure with plenty of access to make connections.
I did get the canopy to move freely. I drilled new holes but was still observing some binding when 4 points were secured. I ended up taking the nylon ball link off the trailing points to leave just the metal ball end in the track. Works perfect.
The difficult part was addressing the main gear. The doors were a simple increase in endpoint adjustment. No big deal there, just 5 more clicks in the open position. The hard part was the left main gear. I took off the oleo and used my #11 blade to bevel off the surrounding area of the printed mount on the door. I also gave the oleo a good rub down with the extra fine steel wool to smooth things out. I re-installed and still found binding. I added some graphite powder to the printed mount and still no joy. The nail in the coffin was when I realized that the front door had too much flex in it. I was noticing this when I would manually move the gear to the down position. I took a strip of carbon tow and used CA to secure it to the front door to stiffen it up. It helped a lot but was still not perfect. I realized that the biggest flex point was right were the mount was where I could not get tow to make stiffer. I used a small piece of balsa triangle stock and secured it to the door and to the mount at the exact angle that was needed. It worked perfect.
I went over a full systems check and found no further issues. She is entirely set for SEFF.
I took a few minutes to boot up RealFlight to get some practice on this one. As I had been tracking the small parts' weight over the build it was fairly accurate but it does not really account for the weight of all the little things I've added. After making a few adjustments to weight I had the CG right and it was behaving how I would expect it to, based on my years of experience. Given how far forward my CG is, I may opt to take off with half flaps just to get her off the ground without having to completely rely on the elevator. Experience has shown that if you stall the elevator on the warbirds it does not end well. Getting her off the ground with sufficient lift and airspeed will be the biggest chore so that I can get her trimmed out and confirm good and bad characteristics.
I leave for SEFF tomorrow afternoon.
The battery hatch had 8 3/4" holes drilled into it and I secured a heavy duty velcro strap to it with medium CA. It holds all three batteries nice and secure with plenty of access to make connections.
I did get the canopy to move freely. I drilled new holes but was still observing some binding when 4 points were secured. I ended up taking the nylon ball link off the trailing points to leave just the metal ball end in the track. Works perfect.
The difficult part was addressing the main gear. The doors were a simple increase in endpoint adjustment. No big deal there, just 5 more clicks in the open position. The hard part was the left main gear. I took off the oleo and used my #11 blade to bevel off the surrounding area of the printed mount on the door. I also gave the oleo a good rub down with the extra fine steel wool to smooth things out. I re-installed and still found binding. I added some graphite powder to the printed mount and still no joy. The nail in the coffin was when I realized that the front door had too much flex in it. I was noticing this when I would manually move the gear to the down position. I took a strip of carbon tow and used CA to secure it to the front door to stiffen it up. It helped a lot but was still not perfect. I realized that the biggest flex point was right were the mount was where I could not get tow to make stiffer. I used a small piece of balsa triangle stock and secured it to the door and to the mount at the exact angle that was needed. It worked perfect.
I went over a full systems check and found no further issues. She is entirely set for SEFF.
I took a few minutes to boot up RealFlight to get some practice on this one. As I had been tracking the small parts' weight over the build it was fairly accurate but it does not really account for the weight of all the little things I've added. After making a few adjustments to weight I had the CG right and it was behaving how I would expect it to, based on my years of experience. Given how far forward my CG is, I may opt to take off with half flaps just to get her off the ground without having to completely rely on the elevator. Experience has shown that if you stall the elevator on the warbirds it does not end well. Getting her off the ground with sufficient lift and airspeed will be the biggest chore so that I can get her trimmed out and confirm good and bad characteristics.
I leave for SEFF tomorrow afternoon.
Packing is about 95% done. I'll be loading up when I get home from work and be on the road as soon as the kids get home from school and I can say my goodbyes.
There was just one more touch I had to do. The pitot needed a cover and I got this nice key chain from VQ models when I ordered the replacement cowl for the Dauntless. Some ribbon was CAed together to make the cover. I'm using my wing bags from the Hawk to protect the wings of the Corsair and the Texan for the journey to GA. Hope it does the trick.
There was just one more touch I had to do. The pitot needed a cover and I got this nice key chain from VQ models when I ordered the replacement cowl for the Dauntless. Some ribbon was CAed together to make the cover. I'm using my wing bags from the Hawk to protect the wings of the Corsair and the Texan for the journey to GA. Hope it does the trick.
Good luck with the maiden, I look forward to your flight report!
PsyBorg
Wake up! Time to fly!
Congratz on a successful maiden. I will assume that crowd was just as awe struck with the Corsair as we were with the Bugatti last year. Can't wait to see this at FFO and watch it fly. How well did the 3d printed tail gear work out? I assume footage will have to wait or will you be able to upload something fir us before SEFF ends?
DUUUUUUDE! That cockpit shot looks absolutely insane! When are you going to do a panel and gunsight?
Aircraft of this caliber are scattered up and down the line here at SEFF. Lots of excitement around it but it was a big win for me.
Additional details in the cockpit are coming.
I did do some minor bending of the gear this evening. If I can find a dremel or a means to put flat spots on my wire, then I may fly again tomorrow. We’ll see.
Additional details in the cockpit are coming.
I did do some minor bending of the gear this evening. If I can find a dremel or a means to put flat spots on my wire, then I may fly again tomorrow. We’ll see.
jaredstrees
Well-known member
That's awesome! Happy to hear of a successful maiden!
Congrats on a successful maiden! I'll bring my little Corsair to FTFF and will challenge you to a Corsair race. To keep it fair I'll limit myself to a single 850mAh battery. 
HilldaFlyer
Well-known member
Way to go. Happy for you.
Many thanks fellas, I got home late last night and got things unpacked. I still need to review the telemetry data and trims on the radio as well as flight footage. I have video of some initial thoughts but I'll be posting video as soon as possible. The video I have is in 4K so it takes awhile to process but I wanted the highest quality. Once I review all of my data and video I'll give a full flight report.
Hope this fills in the blanks. I had a LOT of coverage so this is cut down a lot. Had quite a few chatty Cathys in the background so the music is fairly prominent.
I did look at the TX tonight. 79MPH was my max speed. I turned the music down so that the sound this prop makes can be heard. It really sounds very scale.
I did look at the TX tonight. 79MPH was my max speed. I turned the music down so that the sound this prop makes can be heard. It really sounds very scale.
Ok, so I want to go over a few things from the maiden.
First I want to talk analytics. I've attached a PDF of a chart I've made from the telemetry data. First off, my top speed was 79 MPH. Not bad at all. I was thinking closer to 100 but then I rememberd my previous math was based on a different motor with a higher KV. So, still... she goes at a good clip.
The flight was fairly short at about 2 minutes. Looking all of this data we get a LOT of information. With no flaps, I was taking off at around 30 MPH as indicated by the relaxing of the elevator and continued airspeed. You can see a strong correlation where there is a drop in airspeed after that as I back off the throttle to quickly get a feel for how she slows down and stalls.
What the overall picture of the elevator input tells me is that I do have a nose-heavy aircraft where I am having to feed in quite a bit of elevator. It's fairly jumpy in the graph and I mention in the video how I need to back off my expo. I believe the authority is there... just need to back off the expo so that my response is a bit more toward the center of the stick.
The flaps deployed tell me that I am having to mix in some elevator but barely any. There is a correlation between the flaps deployed, loss in throttle, and maintaining airspeed. I believe I was in a slight dive at this point, which would correlate well with a bit of elevator input.
Upon landing, you can clearly see how I am maintaining very little variation in elevator input as the airspeed drops with the flaps deployed. the abrupt drop in airspeed starts at around 30 MPH, which is a bit difficult to see in the image but when I zoom in on my graph, the slope clearly changes, along with the elevator going to full up.
While I was there the battery packs came down fine and a quick voltage check showed them still at 80% capacity. So My flight timer will be set at 5 minutes and I should have at least another 2 if there is need.
As mentioned in the video, the aileron linkages need to be adjusted slightly. I believe they are rubbing on the wing skin still so I'll have to go at that with a #11 blade. No biggie.
There was a touch of damage from the travel. Below is the worst of it and a little CA quickly patched it up, no sweat.
So, what happened on the landing? Well, I did not grind flat spots on my gear struts. Remember back that I am using the sprung (coiled) wire gear from the retract to the oleo. Flat spots were not ground onto the wire for the oleos and they turned at the higher speed. After getting that done on-site, I realized that the wire was not ground properly on the INSIDE where the wire is secured to the gear that causes the strut to twist as it retracts. So, I need to entirely pull out BOTH retracts and fix this issue. Unfortunately that means a bit of surgery and may leave some ugliness.
No damage to the airplane and now I get to finish out all the other fun details I have planned.
First I want to talk analytics. I've attached a PDF of a chart I've made from the telemetry data. First off, my top speed was 79 MPH. Not bad at all. I was thinking closer to 100 but then I rememberd my previous math was based on a different motor with a higher KV. So, still... she goes at a good clip.
The flight was fairly short at about 2 minutes. Looking all of this data we get a LOT of information. With no flaps, I was taking off at around 30 MPH as indicated by the relaxing of the elevator and continued airspeed. You can see a strong correlation where there is a drop in airspeed after that as I back off the throttle to quickly get a feel for how she slows down and stalls.
What the overall picture of the elevator input tells me is that I do have a nose-heavy aircraft where I am having to feed in quite a bit of elevator. It's fairly jumpy in the graph and I mention in the video how I need to back off my expo. I believe the authority is there... just need to back off the expo so that my response is a bit more toward the center of the stick.
The flaps deployed tell me that I am having to mix in some elevator but barely any. There is a correlation between the flaps deployed, loss in throttle, and maintaining airspeed. I believe I was in a slight dive at this point, which would correlate well with a bit of elevator input.
Upon landing, you can clearly see how I am maintaining very little variation in elevator input as the airspeed drops with the flaps deployed. the abrupt drop in airspeed starts at around 30 MPH, which is a bit difficult to see in the image but when I zoom in on my graph, the slope clearly changes, along with the elevator going to full up.
While I was there the battery packs came down fine and a quick voltage check showed them still at 80% capacity. So My flight timer will be set at 5 minutes and I should have at least another 2 if there is need.
As mentioned in the video, the aileron linkages need to be adjusted slightly. I believe they are rubbing on the wing skin still so I'll have to go at that with a #11 blade. No biggie.
There was a touch of damage from the travel. Below is the worst of it and a little CA quickly patched it up, no sweat.
So, what happened on the landing? Well, I did not grind flat spots on my gear struts. Remember back that I am using the sprung (coiled) wire gear from the retract to the oleo. Flat spots were not ground onto the wire for the oleos and they turned at the higher speed. After getting that done on-site, I realized that the wire was not ground properly on the INSIDE where the wire is secured to the gear that causes the strut to twist as it retracts. So, I need to entirely pull out BOTH retracts and fix this issue. Unfortunately that means a bit of surgery and may leave some ugliness.
No damage to the airplane and now I get to finish out all the other fun details I have planned.
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