TopRc F4U Corsair assembly
03-16-2021, 04:56 AM
#126
The DLE-120 is quite wide at the plug caps because the plugs stick straight out. If they would have put angled plugs on it there would be no problem fitting it into the cowl. Because there are 4 plugs, it would be more difficult to hide them than the 120. I'm putting a VVRC-120 in mine. It is a bit narrower than the DLE-120.
I considered the 120-4, it would have been smooth and a different sound. Too bad they made it so wide.
I considered the 120-4, it would have been smooth and a different sound. Too bad they made it so wide.
03-19-2021, 03:56 AM
#127
I am making my own that looks like the original but the horns on the rod will be as long as I can make them. I am also inserting a brass tube in the base of the rudder to accept the control rod. That way the rudder is easily removed if necessary.
03-23-2021, 09:05 PM
#128
Two questions. Any consensus on gluing in the wing spars as opposed to just using the nylon bold. #2: I have always used baffles with the Saito 90, but I have seen several airplanes flying the 90 without baffles that seem to do fine. Any opinions?
03-24-2021, 01:32 AM
#129
I wanted to leave the wing joiners removable but I was concerned about wing flex . I tested the flex at the wing joiner by picking up the plane by the wing tips , not good. So I epoxied in the joiners to the center section and the flex was greatly reduced , some remained but it is a heavy plane .
. As far as baffling the engine . Unless you have onboard telemetry to see the cylinder temps while flying I wouldn't consider flying without the baffles in place. The engines get hot quick and need all the tricks to keep them cool . I have even removed the rear cowl ring by mounting the cowl to the engine instead of the firewall and opened up the cowl flaps in addition to the baffles to be sure I'm getting enough airflow directly through the cooling fins on the heads .
. As far as baffling the engine . Unless you have onboard telemetry to see the cylinder temps while flying I wouldn't consider flying without the baffles in place. The engines get hot quick and need all the tricks to keep them cool . I have even removed the rear cowl ring by mounting the cowl to the engine instead of the firewall and opened up the cowl flaps in addition to the baffles to be sure I'm getting enough airflow directly through the cooling fins on the heads .
03-27-2021, 09:19 PM
#130
@LTMash,
I’ve flown the Saito 84 in the TF Corsair, a DLE 61 is it now, and the 60 in the Hellcat, a large scale Mr Mulligan with the 90 and none of them had baffles. They run just fine as long as you know the idle temps and the temps when you land and taxi back. The big thing is not over revving them so be sure to prop your engine on the higher side to reduce peak rpm in flight. I have RPM Telemetry and listen to the rpms as I fly through maneuvers. I tune for about 6500rpm max and it will vary between 6500-7000 as you fly. On any given day the weather will also come into play so watch temps and RPM as things change with density altitude. If I know the DAlt will be higher than 4500 feet I don’t fly or I might change the prop to get more bite in thinner air but keep the rpms under 7000.
I check with the airport, just call the tower phone number and they read out the conditions. We’re at 2240 feet ASL and can see DAlt over 6000 feet, bad day to fly. So I usually run one inch larger props or more pitch depending on the engine and plane.
You could easily put in temp telemetry also if you’re that concerned with the installation.
I run Klotz oil exclusively with NON-Ethanol unleaded gas, gap the spark plugs as recommended, and I use Xoar props on all three radials. I’ve run other props, carbon, Mejzlik, Beila, 2 and 3 blade but the Xoar blades have a better profile and the engines perform very well from my testing.
Ive done very detailed baffling on tight cowl 2 stroke installations with great results but so far the Saito radials have not required it. Just keep the cowl airflow nice and open.
Also note that depending on how you mounted the cowl a baffle around radial could get in the way of the cowl hardware if it’s on the inside behind the baffle. Just think ahead about the cowl mounts, hardware and the orientation of the engine to the hardware.
That Corsair looks the business I have to say, enjoy it!
Also, I see you’re running, or going to run, that scale-ish 3 blade prop. I had a bad experience with that same type of prop because it didn’t load up the engine right. It should be a 23 inch prop with about 10 inches of pitch. I typically fly a 24x10 or 12 two blade Xoar. Not sure of the specs on yours but it might tach and sound fine on the ground but in the air it will be different. I had to run the power at a higher than usual setting on final to keep the prop and engine loaded with full flaps. I recommend you fly a two blade prop first then try the three blade once you’re familiar with the Saito. If you know the engine and set up then disregard.
I’ve flown the Saito 84 in the TF Corsair, a DLE 61 is it now, and the 60 in the Hellcat, a large scale Mr Mulligan with the 90 and none of them had baffles. They run just fine as long as you know the idle temps and the temps when you land and taxi back. The big thing is not over revving them so be sure to prop your engine on the higher side to reduce peak rpm in flight. I have RPM Telemetry and listen to the rpms as I fly through maneuvers. I tune for about 6500rpm max and it will vary between 6500-7000 as you fly. On any given day the weather will also come into play so watch temps and RPM as things change with density altitude. If I know the DAlt will be higher than 4500 feet I don’t fly or I might change the prop to get more bite in thinner air but keep the rpms under 7000.
I check with the airport, just call the tower phone number and they read out the conditions. We’re at 2240 feet ASL and can see DAlt over 6000 feet, bad day to fly. So I usually run one inch larger props or more pitch depending on the engine and plane.
You could easily put in temp telemetry also if you’re that concerned with the installation.
I run Klotz oil exclusively with NON-Ethanol unleaded gas, gap the spark plugs as recommended, and I use Xoar props on all three radials. I’ve run other props, carbon, Mejzlik, Beila, 2 and 3 blade but the Xoar blades have a better profile and the engines perform very well from my testing.
Ive done very detailed baffling on tight cowl 2 stroke installations with great results but so far the Saito radials have not required it. Just keep the cowl airflow nice and open.
Also note that depending on how you mounted the cowl a baffle around radial could get in the way of the cowl hardware if it’s on the inside behind the baffle. Just think ahead about the cowl mounts, hardware and the orientation of the engine to the hardware.
That Corsair looks the business I have to say, enjoy it!
Also, I see you’re running, or going to run, that scale-ish 3 blade prop. I had a bad experience with that same type of prop because it didn’t load up the engine right. It should be a 23 inch prop with about 10 inches of pitch. I typically fly a 24x10 or 12 two blade Xoar. Not sure of the specs on yours but it might tach and sound fine on the ground but in the air it will be different. I had to run the power at a higher than usual setting on final to keep the prop and engine loaded with full flaps. I recommend you fly a two blade prop first then try the three blade once you’re familiar with the Saito. If you know the engine and set up then disregard.
Last edited by Chris Nicastro; 03-27-2021 at 09:36 PM.
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LtMash1A (03-28-2021)
04-14-2021, 03:54 PM
#133
I been reading a lot about the Saito, too many horror stories! So I’m feeling uneasy about it plus it’s in back order until June in HH. The Moki 180 is just too expensive to justify it.
04-14-2021, 11:18 PM
#134
I’ve flown the UMS 77cc nitro 7cyl in a large scale model of the Lockheed Sirius, 100 inch WS I think, and it was good. The engine takes forever to break in properly and has a very weak glow system. The cylinders are vulnerable to plugs stripping out because they are cast aluminum. You can get the cylinders upgraded with inserts for the plugs and an ignition system but by then you should just buy a Moki. We had issues with the battery pack for the glow system and no issues with the plugs as of yet. It is a very fuel efficient engine and messy with glow fuel plus exhaust residue but it sounds cool and looks nice in a round cowl.
The Saito 90 is very good and I’ve used it in a large Mr Mulligan with great results. Again scratch built large scale model and it hauled it around with authority. If the engine is broken in on a bench and adjusted accordingly it should run great in the model like we have experienced. The FG84 was a mixed experience because we sent it out for an upgrade service after break in and then it failed on its maiden flight. Subsequent flights have resulted in less performance over time so that engine has been installed in a Gilmore scale race plane project. I’m planning on lapping the valve seats to increase compression on that engine.
From the YouTube videos I’ve seen of the FG90 in these TopRC warbirds it seems it is the best choice of the 4 stroke radials other than a Moki. Some have said it’s the minimum engine choice and it flies scale like, aka underpowered.
Now, there are NEW UMS gas radials I’ve never seen in person that might be better than anything we’re talking about, https://www.morrisminimotors.com/eng...s-engines.html
There are several engines to choose from, no idea what fits and how they work, etc.
If anyone has experience with 90cc and up engines let’s see
The Saito 90 is very good and I’ve used it in a large Mr Mulligan with great results. Again scratch built large scale model and it hauled it around with authority. If the engine is broken in on a bench and adjusted accordingly it should run great in the model like we have experienced. The FG84 was a mixed experience because we sent it out for an upgrade service after break in and then it failed on its maiden flight. Subsequent flights have resulted in less performance over time so that engine has been installed in a Gilmore scale race plane project. I’m planning on lapping the valve seats to increase compression on that engine.
From the YouTube videos I’ve seen of the FG90 in these TopRC warbirds it seems it is the best choice of the 4 stroke radials other than a Moki. Some have said it’s the minimum engine choice and it flies scale like, aka underpowered.
Now, there are NEW UMS gas radials I’ve never seen in person that might be better than anything we’re talking about, https://www.morrisminimotors.com/eng...s-engines.html
There are several engines to choose from, no idea what fits and how they work, etc.
If anyone has experience with 90cc and up engines let’s see
Last edited by Chris Nicastro; 04-14-2021 at 11:22 PM.
04-15-2021, 06:04 AM
#135
Any feedback on UMS radials? Seems the largest that will fit the cowling and produce as much power as the Saito 90R3 is their 5-125.
I been reading a lot about the Saito, too many horror stories! So I’m feeling uneasy about it plus it’s in back order until June in HH. The Moki 180 is just too expensive to justify it.
I been reading a lot about the Saito, too many horror stories! So I’m feeling uneasy about it plus it’s in back order until June in HH. The Moki 180 is just too expensive to justify it.
04-15-2021, 02:15 PM
#136
Any feedback on UMS radials? Seems the largest that will fit the cowling and produce as much power as the Saito 90R3 is their 5-125.
I been reading a lot about the Saito, too many horror stories! So I’m feeling uneasy about it plus it’s in back order until June in HH. The Moki 180 is just too expensive to justify it.
I been reading a lot about the Saito, too many horror stories! So I’m feeling uneasy about it plus it’s in back order until June in HH. The Moki 180 is just too expensive to justify it.
The UMS 5-125 will not fit - to large in diameter. I attempted a swap out three weeks ago.
04-15-2021, 05:21 PM
#138
I originally had the 7-90 in it and it fit nicely, but required about 4.5lbs of lead to balance it out. I thought the 5-125 would but unless you cut holes for the rocker arms it will Not. I have a Moki 180 that I will try later.
Since I was fiddling with the 5-125 I got side-tracked and put it in a Phoenix Waco ready to maiden possibly this week.
04-19-2021, 10:03 PM
#139
I originally had the 7-90 in it and it fit nicely, but required about 4.5lbs of lead to balance it out. I thought the 5-125 would but unless you cut holes for the rocker arms it will Not. I have a Moki 180 that I will try later.
Since I was fiddling with the 5-125 I got side-tracked and put it in a Phoenix Waco ready to maiden possibly this week.
Since I was fiddling with the 5-125 I got side-tracked and put it in a Phoenix Waco ready to maiden possibly this week.
Running out of options, what about the 5-100? it is 9.44” in diameter, so it should fit, but only 11.5kg of thrust, think that may not be enough to fly this plane...
05-09-2021, 05:09 PM
#140
05-12-2021, 04:49 AM
#143
The DLE-85 will have good power, and cooling will not be an issue with the hole in the cowl for the head. I would keep an eye on the airframe though. Typically the TopRC warbirds don't handle vibration very well. Using a twin is quite a bit smoother, but it's a tight fit in the cowl.
05-20-2021, 04:50 PM
#147
My Feedback: (6)
Well I ordered from them because they showed "In Stock" at the time. They currently still show In Stock.on their website as of today. So I guess they weren't when they took my order. Honestly, them showing in stock is the only reason I ordered the plane from Robart.....it was the second to last one they had in stock.
I've sent emails with no response, and they aren't answering the phone. Really not feeling the love right now.....
I've sent emails with no response, and they aren't answering the phone. Really not feeling the love right now.....
05-21-2021, 07:00 AM
#148
I got some info from Dan at Robart, they are still having supplier issues, but expect to have the retracts in a couple weeks or so. I received my Corsair back in February.
I didn't really plan on building it in time for this season anyway, but I'm sure some expected to get the plane in the air this spring. Hopefully we'll see the gear soon.
I didn't really plan on building it in time for this season anyway, but I'm sure some expected to get the plane in the air this spring. Hopefully we'll see the gear soon.
05-22-2021, 09:06 AM
#149
My Feedback: (6)
Thanks Todd,
Is that the Robart brand retracts they hope to have in a few weeks, or will they also be selling the Top RC ones? Can't imagine that but just asking...
For the record, Legend won't even respond to say yes, no, maybe. They are just showing them as in stock and taking your money over the internet. I'm going to have to go to my credit card company to get a refund I guess.
Is that the Robart brand retracts they hope to have in a few weeks, or will they also be selling the Top RC ones? Can't imagine that but just asking...
For the record, Legend won't even respond to say yes, no, maybe. They are just showing them as in stock and taking your money over the internet. I'm going to have to go to my credit card company to get a refund I guess.
05-22-2021, 03:11 PM
#150
Thanks Todd,
Is that the Robart brand retracts they hope to have in a few weeks, or will they also be selling the Top RC ones? Can't imagine that but just asking...
For the record, Legend won't even respond to say yes, no, maybe. They are just showing them as in stock and taking your money over the internet. I'm going to have to go to my credit card company to get a refund I guess.
Is that the Robart brand retracts they hope to have in a few weeks, or will they also be selling the Top RC ones? Can't imagine that but just asking...
For the record, Legend won't even respond to say yes, no, maybe. They are just showing them as in stock and taking your money over the internet. I'm going to have to go to my credit card company to get a refund I guess.
I've dealt with Legend before, they are usually pretty good to work with. If you are able to contact them, I'm sure they'd let you know what the issue is with the TopRC retracts.