Yellow Aircraft F-18 single P-60 maiden
11-25-2012, 04:13 PM
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Yellow Aircraft F-18 single P-60 maiden
Hello Everybody,
Finally my F-18 had her maiden flight today. Unfortunately there is no video, since my camera was so involved in the flight that forgot to press the recording button.
https://picasaweb.google.com/lh/phot...eat=directlink
This plane was originally intended for Dynamax DF, but converted to turbine power with a JetCat P-60 SE. Dry weight is about 7.6kg and loaded with fuel 8.45Kg (1.7L) way above the 6kg mentioned in the manual
First maiden attempt was actually last weekend but the combination of the semi scale struts and a side wind made impossible to get enough speed for take off and I aborted in the hope of a more adequate weather.
The problem with these struts is that are spring loaded with a range of motion of more that 6cm. With a side wind, the plane leans on one side until the wing tip touches the runway. This side leaning also affect the direction making almost impossible to maintain the plane centered in the runway for take off.
Today the sky was overcast and the runway was still wet.
Following the manual advice I had flaps one step down (take off position) and long throws
Our track is 150m asphalt.
After about 100 meters of runway at full power, the plane had no intention to take off by itself so I pulled the elevator gently. At the end of the runway there is a wall of dirt, so if the plane wouldn't take off might end up completely dumped. So in the last 25 meters I pulled the elevator to a full up and hoped for the best... It happened, she took off with a shallow climb and I was able to retract the gear and ease the elevator as speed built up. it took some seconds and a wide turn to build up enough speed to set flaps to the 0ΒΊ position and start trimming. The model actually needed around 8 click elevator up to maintain an even attitude. Several circuits later I prepare for landing, what I feared the most due to the excess of weight.
Flaps full down, undercarriage out and on the final approach, turbine at idle. Slowly the nose points up as the speed is drained and touches gently with the main gear. Nose gear down and start to brake... leans right, wing tip scratches the asphalt , release brake... another attempt of braking, leans left wing tip scratches the asphalt. Release brakes and let the plane go to a full stop by itself.
Overall the plane was very pleasant to ply although it felt a little underpowered, specially during take off. The bifurcated pipe seems to be hurting quite a lot the performance of the P-60
I wonder if any of you could give some advice on these semi scale struts (original for YA) so the plane can be more stable on the ground and save my wing tips!.
Thanks to Rick for the electronic copy of the manual, without the proper throws and GC, this would have been a complete disaster.
Regards
JMM
Finally my F-18 had her maiden flight today. Unfortunately there is no video, since my camera was so involved in the flight that forgot to press the recording button.
https://picasaweb.google.com/lh/phot...eat=directlink
This plane was originally intended for Dynamax DF, but converted to turbine power with a JetCat P-60 SE. Dry weight is about 7.6kg and loaded with fuel 8.45Kg (1.7L) way above the 6kg mentioned in the manual
First maiden attempt was actually last weekend but the combination of the semi scale struts and a side wind made impossible to get enough speed for take off and I aborted in the hope of a more adequate weather.
The problem with these struts is that are spring loaded with a range of motion of more that 6cm. With a side wind, the plane leans on one side until the wing tip touches the runway. This side leaning also affect the direction making almost impossible to maintain the plane centered in the runway for take off.
Today the sky was overcast and the runway was still wet.
Following the manual advice I had flaps one step down (take off position) and long throws
Our track is 150m asphalt.
After about 100 meters of runway at full power, the plane had no intention to take off by itself so I pulled the elevator gently. At the end of the runway there is a wall of dirt, so if the plane wouldn't take off might end up completely dumped. So in the last 25 meters I pulled the elevator to a full up and hoped for the best... It happened, she took off with a shallow climb and I was able to retract the gear and ease the elevator as speed built up. it took some seconds and a wide turn to build up enough speed to set flaps to the 0ΒΊ position and start trimming. The model actually needed around 8 click elevator up to maintain an even attitude. Several circuits later I prepare for landing, what I feared the most due to the excess of weight.
Flaps full down, undercarriage out and on the final approach, turbine at idle. Slowly the nose points up as the speed is drained and touches gently with the main gear. Nose gear down and start to brake... leans right, wing tip scratches the asphalt , release brake... another attempt of braking, leans left wing tip scratches the asphalt. Release brakes and let the plane go to a full stop by itself.
Overall the plane was very pleasant to ply although it felt a little underpowered, specially during take off. The bifurcated pipe seems to be hurting quite a lot the performance of the P-60
I wonder if any of you could give some advice on these semi scale struts (original for YA) so the plane can be more stable on the ground and save my wing tips!.
Thanks to Rick for the electronic copy of the manual, without the proper throws and GC, this would have been a complete disaster.
Regards
JMM
11-25-2012, 04:34 PM
#2
RE: Yellow Aircraft F-18 single P-60 maiden
I've had one of these and they are a great flying jet.. I first flew it off a grass runway and it used every mm of the strip.. I later converted it to a wren 54 mk 3 which had a little more thrust.. Got off grass a little better and the flight performance was noticeably better..
I'm now in the process off biulding another one but this time have gone for the tamjets tail pipe and a jet munts vt80 which puts out 18lbs of thrust.. Can't wait to fly it. As for your YA leg problems I never had any dramas but in saying that only ever flew it with a head wind.. And always let the jet roll out as I did experience scuffing a wing tip when brakes were applied..
I'm now in the process off biulding another one but this time have gone for the tamjets tail pipe and a jet munts vt80 which puts out 18lbs of thrust.. Can't wait to fly it. As for your YA leg problems I never had any dramas but in saying that only ever flew it with a head wind.. And always let the jet roll out as I did experience scuffing a wing tip when brakes were applied..
11-25-2012, 08:46 PM
#4
RE: Yellow Aircraft F-18 single P-60 maiden
Jose,
First off, congrats on the maiden! I'm glad you got her up and down in one piece. I have a few questions about your installation, but it would be easier if you could just post some pics of the install, particularly the fuel setup and the spacing between your engine and pipe. I've built and flown several of these, and have worked the bugs out (pretty much) and haven't experienced the problems you're describing in quite some time.
For one thing, the wingtip dance has very little to do with the springs in the mains. If they're stock, they're only strong enough to return the struts to the extended position with the weight off of the gear. They won't be strong enough to push the plane up off of the ground, especially if you're heavy. What you need to do is make sure that you have at least 1.5 degrees of toe-in on the mains, and that there's absolutely no slop on the main gear. If you use your hand to articulate the gear aft, you should not be able to sway the wheel left or right at all. If you can detect any slop there, it will amplify significantly on the ground. Also, I recommend that you ensure that the nose strut is not angled forward, and that you have some expo programmed into the steering.
Depending on where you're carrying your fuel, you might need a great deal of takeoff roll and 25 degrees of flaps for takeoff using the recommended CG. Once you're moving, the P-60 is PLENTY of power for that plane (assuming you've got your pipe setup proper).
So, let's see some pics of the inside?
First off, congrats on the maiden! I'm glad you got her up and down in one piece. I have a few questions about your installation, but it would be easier if you could just post some pics of the install, particularly the fuel setup and the spacing between your engine and pipe. I've built and flown several of these, and have worked the bugs out (pretty much) and haven't experienced the problems you're describing in quite some time.
For one thing, the wingtip dance has very little to do with the springs in the mains. If they're stock, they're only strong enough to return the struts to the extended position with the weight off of the gear. They won't be strong enough to push the plane up off of the ground, especially if you're heavy. What you need to do is make sure that you have at least 1.5 degrees of toe-in on the mains, and that there's absolutely no slop on the main gear. If you use your hand to articulate the gear aft, you should not be able to sway the wheel left or right at all. If you can detect any slop there, it will amplify significantly on the ground. Also, I recommend that you ensure that the nose strut is not angled forward, and that you have some expo programmed into the steering.
Depending on where you're carrying your fuel, you might need a great deal of takeoff roll and 25 degrees of flaps for takeoff using the recommended CG. Once you're moving, the P-60 is PLENTY of power for that plane (assuming you've got your pipe setup proper).
So, let's see some pics of the inside?
11-26-2012, 02:35 AM
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RE: Yellow Aircraft F-18 single P-60 maiden
Hello Shaun,
Both of your hints seem to be leading to the right direction. After post flight inspection I found that there was a little slop on the main gear and the set screws had come loose. I reseated all back to the original 1.5ΒΊ toe in, fully tightened the setscrew on the wide flat spot on the retract spar and fix them with a drop of blue thread locker, in the hope it wont come loose again.
During the original assembly I foresaw the problem with the springs and I already cut them so they have just enought length to restore the let to the straight position in the wells. There is absolutely no suspension when the plane is sittign on its weels.
The pipe-turbine distance has been a matter of discussion with the pipe manufacturer from the begining. He states that the nozzle of the turbine has to sit inside the pipe by 2cm although I have always read that it has to be outside the pipe by 2cm. Since it is my fist pipe, I followed the manufacturer directions, but always sounded wrong to me.
Some pictures of the setup:
https://picasaweb.google.com/lh/phot...eat=directlink
https://picasaweb.google.com/lh/phot...eat=directlink
BTW.
Where coudl I get some blue and golden paint that matches the kit for the small repairs?
Thanks in advance and best regards,
JMM
Both of your hints seem to be leading to the right direction. After post flight inspection I found that there was a little slop on the main gear and the set screws had come loose. I reseated all back to the original 1.5ΒΊ toe in, fully tightened the setscrew on the wide flat spot on the retract spar and fix them with a drop of blue thread locker, in the hope it wont come loose again.
During the original assembly I foresaw the problem with the springs and I already cut them so they have just enought length to restore the let to the straight position in the wells. There is absolutely no suspension when the plane is sittign on its weels.
The pipe-turbine distance has been a matter of discussion with the pipe manufacturer from the begining. He states that the nozzle of the turbine has to sit inside the pipe by 2cm although I have always read that it has to be outside the pipe by 2cm. Since it is my fist pipe, I followed the manufacturer directions, but always sounded wrong to me.
Some pictures of the setup:
https://picasaweb.google.com/lh/phot...eat=directlink
https://picasaweb.google.com/lh/phot...eat=directlink
BTW.
Where coudl I get some blue and golden paint that matches the kit for the small repairs?
Thanks in advance and best regards,
JMM
11-26-2012, 02:44 AM
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RE: Yellow Aircraft F-18 single P-60 maiden
Hello Tisdall,
Do you have any pictures of your old and the new one? There may be an issue with my pipe to turbine setup and if yours was working fine, would be helpful to see the differences. I woudl also love to see overall pictures for both of your bugs, in any case.
I am in the process of getting a f-4 also from YellowA. It is incredible how difficult are they to find nowadays in Spain. I have one in my radar but has been sitting on a warehouse for 15 years... I wonder if the glass fiber or resins degrade with the time...
Regards,
JMM
Do you have any pictures of your old and the new one? There may be an issue with my pipe to turbine setup and if yours was working fine, would be helpful to see the differences. I woudl also love to see overall pictures for both of your bugs, in any case.
I am in the process of getting a f-4 also from YellowA. It is incredible how difficult are they to find nowadays in Spain. I have one in my radar but has been sitting on a warehouse for 15 years... I wonder if the glass fiber or resins degrade with the time...
Regards,
JMM
11-26-2012, 04:03 AM
#7
RE: Yellow Aircraft F-18 single P-60 maiden
Hi JMM.. I have a biuld thread on here showing my latest one in various stages.. Looking at your pics it appears that your turbine is set too far back into the bifurbicated pipe.. That could be part of your lack of power problem.. From memory I think you want about 25mm from turbine exhaust tip to the start of tail pipe..
Cheers Andrew
Cheers Andrew
11-26-2012, 07:35 AM
#8
RE: Yellow Aircraft F-18 single P-60 maiden
Jose,
I think your pipe is definitely part of the problem. With an open install like that, I think you would be well served to have a bell-mouth on that pipe, and the engine moved to about 1/2" in front of the opening of the bell-mouth. You're likely to see a noticeable power increase. Is all of your fuel carried in that tank in your picture? Are you not using the conformal cells as well?
I think your pipe is definitely part of the problem. With an open install like that, I think you would be well served to have a bell-mouth on that pipe, and the engine moved to about 1/2" in front of the opening of the bell-mouth. You're likely to see a noticeable power increase. Is all of your fuel carried in that tank in your picture? Are you not using the conformal cells as well?
11-26-2012, 08:11 AM
#9
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RE: Yellow Aircraft F-18 single P-60 maiden
I agree with Shaun about the pipe, that certainly could result in a power loss the way it is currently installed. I'm also wondering about your balance, sounds as if could be nose heavy. Lack of rotation on take off, up trim for level fight...
11-26-2012, 11:01 AM
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RE: Yellow Aircraft F-18 single P-60 maiden
Hello guys,
Thanks for your help and ideas so far.
GC is per plan with the fuel tank empy and gear retracted. It feels right flying and on the final approach the nose rose easily. It may be something to play with once I figure out how to remove the casted pieze of lead I fixed in the nose with plenty of epoxi.
I am using both the conformal cells and the main fuel tank. all 3 tanks are daisy chained, being the conformal cells drained first. For taxiing I use a 4th extenal tank connected to the spill nipple.
Being a custom made pipe is almost imposible to find a suitable bell mouth. But I can easily cut a strip of metal from the pipe and move the turbine a couple of cm to the front to get the 1.25 cm clearance suggested. Would that work without the bell mouth? or will the pipe collapse over itself..
Cheers
Jose
Thanks for your help and ideas so far.
GC is per plan with the fuel tank empy and gear retracted. It feels right flying and on the final approach the nose rose easily. It may be something to play with once I figure out how to remove the casted pieze of lead I fixed in the nose with plenty of epoxi.
I am using both the conformal cells and the main fuel tank. all 3 tanks are daisy chained, being the conformal cells drained first. For taxiing I use a 4th extenal tank connected to the spill nipple.
Being a custom made pipe is almost imposible to find a suitable bell mouth. But I can easily cut a strip of metal from the pipe and move the turbine a couple of cm to the front to get the 1.25 cm clearance suggested. Would that work without the bell mouth? or will the pipe collapse over itself..
Cheers
Jose
11-26-2012, 03:20 PM
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RE: Yellow Aircraft F-18 single P-60 maiden
Hey Tisdall
I noticed that your tube ends INSIDE the fuselage turkey feathers. That is really cool!
How can this be done safely? how can be a double walled pipe be chopped without damaging it?
Cheers
Jose
I noticed that your tube ends INSIDE the fuselage turkey feathers. That is really cool!
How can this be done safely? how can be a double walled pipe be chopped without damaging it?
Cheers
Jose
11-26-2012, 05:17 PM
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RE: Yellow Aircraft F-18 single P-60 maiden
i have this same Jet from 6 years ago never flown i went to bigger one,s but getting the urge to put a P-70 in it because it is flight ready look at my pic. and you will see it has a bell mouh and conformal tanks around the C.G point i think
11-28-2012, 03:53 AM
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RE: Yellow Aircraft F-18 single P-60 maiden
Gentlemen,
I have trimmed the pipe and moved the turbine for proper clearance. Also noticed that my thrust pipe wasaiming a little down,maybe could be part of the problem...
https://lh6.googleusercontent.com/-Y...0/IMG_0600.JPG
Regards,
Jose
I have trimmed the pipe and moved the turbine for proper clearance. Also noticed that my thrust pipe wasaiming a little down,maybe could be part of the problem...
https://lh6.googleusercontent.com/-Y...0/IMG_0600.JPG
Regards,
Jose
11-28-2012, 04:20 PM
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RE: Yellow Aircraft F-18 single P-60 maiden
I have a custom hatch to ease the positioning of the pipe. Without this custom hatch, was very difficult to work on the pipe.
Cheers,
Jose
Cheers,
Jose
