The New F86D Dog Sabre
08-19-2014, 08:23 PM
#1103
My Feedback: (2)
ha you have a long road ahead of you! 
/
good luck with your build. There's a wealth of knowledge in this thread. Read it carefully.
Sid, I overlooked the fact your 27mph reporting was on your Cosmic Wind. Sorry.
My F86 weight is around 18.5lbs, stall speed is 35mph. In the approach, I turn base at 55mph, turn final at around 50, and try to cross the numbers at 45mph. No CROW in this one. I do have a rudder gyro. No sign of wing rocking when it gets slow.
Quandry, you should really heed the advise to rework the flaps so you can put the hinge at the botttom. I didn't do that, thus it's more difficult to bleed off speed as I can't quite get a 45 deg flap angle. It's not a show stopper, but it probably would be easier to land.
/good luck with your build. There's a wealth of knowledge in this thread. Read it carefully.
Sid, I overlooked the fact your 27mph reporting was on your Cosmic Wind. Sorry.
My F86 weight is around 18.5lbs, stall speed is 35mph. In the approach, I turn base at 55mph, turn final at around 50, and try to cross the numbers at 45mph. No CROW in this one. I do have a rudder gyro. No sign of wing rocking when it gets slow.
Quandry, you should really heed the advise to rework the flaps so you can put the hinge at the botttom. I didn't do that, thus it's more difficult to bleed off speed as I can't quite get a 45 deg flap angle. It's not a show stopper, but it probably would be easier to land.
Pull Up
Thanks for the info on air speeds for the F-86D. I hope to have mine flying this fall and will compare your speeds to mine. I will be flying at 5750 msl so will see if I need to up my numbers a little. Since I plan on using the speed brakes for drag I will set the flaps for max lift for landing.
08-24-2014, 12:59 PM
#1104
ha you have a long road ahead of you! /
good luck with your build. There's a wealth of knowledge in this thread. Read it carefully.
Sid, I overlooked the fact your 27mph reporting was on your Cosmic Wind. Sorry.
My F86 weight is around 18.5lbs, stall speed is 35mph. In the approach, I turn base at 55mph, turn final at around 50, and try to cross the numbers at 45mph. No CROW in this one. I do have a rudder gyro. No sign of wing rocking when it gets slow.
Quandry, you should really heed the advise to rework the flaps so you can put the hinge at the botttom. I didn't do that, thus it's more difficult to bleed off speed as I can't quite get a 45 deg flap angle. It's not a show stopper, but it probably would be easier to land.
/good luck with your build. There's a wealth of knowledge in this thread. Read it carefully.
Sid, I overlooked the fact your 27mph reporting was on your Cosmic Wind. Sorry.
My F86 weight is around 18.5lbs, stall speed is 35mph. In the approach, I turn base at 55mph, turn final at around 50, and try to cross the numbers at 45mph. No CROW in this one. I do have a rudder gyro. No sign of wing rocking when it gets slow.
Quandry, you should really heed the advise to rework the flaps so you can put the hinge at the botttom. I didn't do that, thus it's more difficult to bleed off speed as I can't quite get a 45 deg flap angle. It's not a show stopper, but it probably would be easier to land.
08-28-2014, 02:10 AM
#1105
Guys just an update - here is my approach to the flap mod on the Dog Sabre.
In the Modelbau instructions, the manufacturer recommends that the flaps achieve 55mm of flap travel for landing and that it may be necessary to 'hinge at the bottom' to achieve this. It looked to me though that even when doing this the flap would foul against the wing root at the top due to the whole thing pivoting much lower on the wing. I might be wrong - but that's just what it looked like to me so I decided to try a different method.
Holding the flap in place (but not installed), I could see that I get roughly 30mm of travel out of the box.
The reason why it can't go any further is that the flap contacts the wing due to the profile. By reprofiling the flap, it will be possible to increase travel. To achieve this I held the flap over some cardboard, marked out a template, cut it out and then proceeded to modify the template until I could achieve the level of travel I am looking for
I then put painters tape around the flap to mark the cut line in accordance with the template. It's very easy just mark the sides first then use a ruler and pen to join up the lines. For the leading edge, I used the actual flap line as the line I will cut to. This means I can achieve maximum throw without the hinge itself blocking any travel.
In the Modelbau instructions, the manufacturer recommends that the flaps achieve 55mm of flap travel for landing and that it may be necessary to 'hinge at the bottom' to achieve this. It looked to me though that even when doing this the flap would foul against the wing root at the top due to the whole thing pivoting much lower on the wing. I might be wrong - but that's just what it looked like to me so I decided to try a different method.
Holding the flap in place (but not installed), I could see that I get roughly 30mm of travel out of the box.
The reason why it can't go any further is that the flap contacts the wing due to the profile. By reprofiling the flap, it will be possible to increase travel. To achieve this I held the flap over some cardboard, marked out a template, cut it out and then proceeded to modify the template until I could achieve the level of travel I am looking for
I then put painters tape around the flap to mark the cut line in accordance with the template. It's very easy just mark the sides first then use a ruler and pen to join up the lines. For the leading edge, I used the actual flap line as the line I will cut to. This means I can achieve maximum throw without the hinge itself blocking any travel.
08-28-2014, 02:10 AM
#1106
Using a sharp exacto style blade and moving slowly, it is possible to move all the way around the cut lines and essentially shave the flap to the right profile. The piece seems to be a solid chunk of balsa so it's very easy to cut.
Now it is possible to install the hinges in the flap piece and cover the exposed balsa with some silver tape or covering. The advantage of performing work in this area is that it is hidden away underneath the wing in a shaded area that is hard to see. Having a slightly different silver will not matter too much. As you can see by this picture the flap profile is changed only slightly however it makes a big difference as to how much throw can be achieved with the hinge in the stock location.
It may yet be necessary for me to redesign the flap horn slightly to accomodate this change - but for me this is a fun part of the hobby -trial and error to achieve!
Now it is possible to install the hinges in the flap piece and cover the exposed balsa with some silver tape or covering. The advantage of performing work in this area is that it is hidden away underneath the wing in a shaded area that is hard to see. Having a slightly different silver will not matter too much. As you can see by this picture the flap profile is changed only slightly however it makes a big difference as to how much throw can be achieved with the hinge in the stock location.
It may yet be necessary for me to redesign the flap horn slightly to accomodate this change - but for me this is a fun part of the hobby -trial and error to achieve!
09-09-2014, 05:12 PM
#1107
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I was buddy boxed 3 more flights on my dog this past weekend. There was a strong cross-wind for all flights and I found the ailerons very "mushy" during set-up and approach. It may be my lack flying time on jets, but it was uncomfortable. My trainer had no issues, thanks! The reworked strut worked great and take-offs were a breeze. Maybe next trip I can shoot some landings.
Sorry, still no vid's!
Happy flying,
Sorry, still no vid's!
Happy flying,
09-30-2014, 05:25 PM
#1108
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10-01-2014, 12:48 AM
#1110
My build continues...
I had a pilot/cockpit left over from a previous project. He is probably not the exact right scale, but close enough for me anyways...
I'm going to have a couple of spare channels on my RX setup so figured I would do some customising and have a turnable head.
After some dremel work and epoxy..
And this is what it looks like altogether (sorry for the busy pic, I'll get a better one when I have the undercarriage installed)
Last night I went through all of the mounts/formers and reglued some that had broken loose in transit, I'm now ready to tackle the turbine mount and pipe install. After a quick dry fit I can see that the Kingtech 100 is a tight squeeze in there but it will go. Wish me luck!
I had a pilot/cockpit left over from a previous project. He is probably not the exact right scale, but close enough for me anyways...
I'm going to have a couple of spare channels on my RX setup so figured I would do some customising and have a turnable head.
After some dremel work and epoxy..
And this is what it looks like altogether (sorry for the busy pic, I'll get a better one when I have the undercarriage installed)
Last night I went through all of the mounts/formers and reglued some that had broken loose in transit, I'm now ready to tackle the turbine mount and pipe install. After a quick dry fit I can see that the Kingtech 100 is a tight squeeze in there but it will go. Wish me luck!
10-01-2014, 12:51 AM
#1111
My build continues...
I had a pilot/cockpit left over from a previous project. He is probably not the exact right scale, but close enough for me anyways...
I'm going to have a couple of spare channels on my RX setup so figured I would do some customising and have a turnable head.
After some dremel work and epoxy..
And this is what it looks like altogether (sorry for the busy pic, I'll get a better one when I have the undercarriage installed)
Last night I went through all of the mounts/formers and reglued some that had broken loose in transit, I'm now ready to tackle the turbine mount and pipe install. After a quick dry fit I can see that the Kingtech 100 is a tight squeeze in there but it will go. Wish me luck!
I had a pilot/cockpit left over from a previous project. He is probably not the exact right scale, but close enough for me anyways...
I'm going to have a couple of spare channels on my RX setup so figured I would do some customising and have a turnable head.
After some dremel work and epoxy..
And this is what it looks like altogether (sorry for the busy pic, I'll get a better one when I have the undercarriage installed)
Last night I went through all of the mounts/formers and reglued some that had broken loose in transit, I'm now ready to tackle the turbine mount and pipe install. After a quick dry fit I can see that the Kingtech 100 is a tight squeeze in there but it will go. Wish me luck!
10-09-2014, 01:21 AM
#1112
Well I got my pipe and front plate mount installed relatively OK. Luckilly my wingman and good buddy Jay had dropped around to the house so the job of checking, measuring, adjusting etc was made easier with a couple of sets of hands. I did dremel away a little bit too much bodywork at the back so I will need to make a small rear mount also to stop the pipe moving side to side but overall that's not a big issue - I prefer to have the ability for air to move freely around the pipe.
While the Aeropoxy was drying on all of that I spent some time figuring out how my front nose wheel and steering will work. As I mentioned previously I am going electric rather than air on this build, no real reason why just personal preference. After raiding my spare parts draw I have an Eflite 46 size full metal retract and Jet 1a leg and wheel. Yes they are definately not scale looking, however on the grass runways I use I would prefer to have a good pivoting style trailing leg.
The rail system that shipped with the kit was too low for this retract design so I had to do some agressive dremelling and then re-inforcing to get my home made birch/carbon retract plates to fit. At the moment these are just screwed in place, I may yet come back and Aeropoxy it all in there - I want to see how it works first.
The nose leg is a bit on the short side so I will try to make an extended pin, if that does not give me the length I need then I may be back to Jet 1a for a longer leg. Will keep you all posted!
While the Aeropoxy was drying on all of that I spent some time figuring out how my front nose wheel and steering will work. As I mentioned previously I am going electric rather than air on this build, no real reason why just personal preference. After raiding my spare parts draw I have an Eflite 46 size full metal retract and Jet 1a leg and wheel. Yes they are definately not scale looking, however on the grass runways I use I would prefer to have a good pivoting style trailing leg.
The rail system that shipped with the kit was too low for this retract design so I had to do some agressive dremelling and then re-inforcing to get my home made birch/carbon retract plates to fit. At the moment these are just screwed in place, I may yet come back and Aeropoxy it all in there - I want to see how it works first.
The nose leg is a bit on the short side so I will try to make an extended pin, if that does not give me the length I need then I may be back to Jet 1a for a longer leg. Will keep you all posted!
10-13-2014, 07:02 PM
#1115
A while ago, Hobby King had an F86 cockpit kit that worked in this Modellbau F86, but they haven't had it for a while. To see what it looks like, see Quandry's post #1110. Doesn't look like that will ever come back, but the other day I tried BVM jets. They have a 63" F86 turbine kit and also a cockpit. I talked to a very nice "Heather" and she sent me closeup photos including measurements. I'm almost positive this BVM cockpit kit will work. It's not a ARF like the Hobby King was, but it beats starting from scratch by a long ways for under $100. I will order one tomorrow and report how it works. As far as I know, it's the only real decent alternative out there.
10-24-2014, 07:15 PM
#1116
I did go ahead and buy the BVM F86 and Fury cockpit kit. As it turned out, extensive cutting was required to make it work. BVM's is a bit too wide for the Saber Dog, so I had to cut it in half and take some out of the middle. It's not perfect, but the illusion is favorable. Here's a picture of the final cockpit.
11-30-2014, 05:32 AM
#1119
Hi guys, I'm just about to pull the trigger on my electric under carriage for the Sabre. In the meantime, I've got the new in box Spring Air retracts, struts, and wheels with brakes that are looking for a new home. As these could really be fitted to a variety of 60-100 size jets I've put them up on ebay for what I feel is an attractive price:
http://www.ebay.co.uk/itm/RC-Jet-Ret...item3a9cb94818
Any other Dog action happening in the forum?
http://www.ebay.co.uk/itm/RC-Jet-Ret...item3a9cb94818
Any other Dog action happening in the forum?
11-30-2014, 05:52 AM
#1120
not sure how many us dollars that works out to, but I hope you've thought through the fact that electric retracts will, by nature, deploy slowly. In an emergency such as an engine flameout, unless you really have quick situational awareness your gears may be only partially down when you dead stick. This of course is will probably cause more damage than if they were't down at all.
This actually happened to me on a large P47 Thunderbolt this last summer. On a jet, there is so much to worry about besides gear realism that I think the Spring Airs give some peace of mind. Also, this jet is anything but realistic anyway. Flies well, though.
This actually happened to me on a large P47 Thunderbolt this last summer. On a jet, there is so much to worry about besides gear realism that I think the Spring Airs give some peace of mind. Also, this jet is anything but realistic anyway. Flies well, though.
12-02-2014, 03:31 AM
#1121
not sure how many us dollars that works out to, but I hope you've thought through the fact that electric retracts will, by nature, deploy slowly. In an emergency such as an engine flameout, unless you really have quick situational awareness your gears may be only partially down when you dead stick. This of course is will probably cause more damage than if they were't down at all.
This actually happened to me on a large P47 Thunderbolt this last summer. On a jet, there is so much to worry about besides gear realism that I think the Spring Airs give some peace of mind. Also, this jet is anything but realistic anyway. Flies well, though.
This actually happened to me on a large P47 Thunderbolt this last summer. On a jet, there is so much to worry about besides gear realism that I think the Spring Airs give some peace of mind. Also, this jet is anything but realistic anyway. Flies well, though.
anyway, regarding the price it's in Euro with a rough calculation they're at $63 USD at the moment. Not bad for 3 x retracts + legs + wheels with brakes!
02-23-2015, 10:40 AM
#1122
Well Winter is starting to fade here so I decided it was time to take out the Dog and do some more assembly to be ready for the start of Jet season 2015.
First job was to make up a rear mount for the pipe. A little bit of a fiddly job, however I got that hysoled in to place and the pipe is aligned and solid now:
Next job then was to fit the canopy. I had a hobby king cockpit and pilot from some years ago that I grafted in there. I've also servo actuated the pilots head so looking forward to a little touch of realism.
I've also been working on the fuel tanks, which have their own challenges in terms of mounting and also sorting out the fittings. I glued in some alloy rings to suit the BVM kero bung kit. It's coming together now but I have to say the shape of the tanks is making it difficult to find the correct length for the clunk. Anyway one tank done, one remains...
I also put the wings on to take a good look at her and I was really impressed, I couldn't help being a little dissapointed that Modelbau USA is gone now as while there are some quality quirks to contend with the Dog is a cool machine.
First job was to make up a rear mount for the pipe. A little bit of a fiddly job, however I got that hysoled in to place and the pipe is aligned and solid now:
Next job then was to fit the canopy. I had a hobby king cockpit and pilot from some years ago that I grafted in there. I've also servo actuated the pilots head so looking forward to a little touch of realism.
I've also been working on the fuel tanks, which have their own challenges in terms of mounting and also sorting out the fittings. I glued in some alloy rings to suit the BVM kero bung kit. It's coming together now but I have to say the shape of the tanks is making it difficult to find the correct length for the clunk. Anyway one tank done, one remains...
I also put the wings on to take a good look at her and I was really impressed, I couldn't help being a little dissapointed that Modelbau USA is gone now as while there are some quality quirks to contend with the Dog is a cool machine.
03-02-2015, 03:49 AM
#1124
Thank you Bill!
Just by way of an update, over the weekend I tidied up some tail wiring, ceramic painted the blast area around the back of the turbine exit, and also spent some time getting my tanks installed. I used BVM fittings and felt clunks in the tanks themselves including a nice set of alloy collars I picked up at Jetpower last year. The manual says to secure the tanks by gluing them in, however I wanted to make mine removable for maintenance purposes so this introduced a new set of complexities....
In the end, I glued down some foam as a base for the tanks, setup quality hook and look against the side wall of the plane, and also came up with a velcro strap system in order to hold them firmly in position. They're gripped on a few sides so I don't anticipate any issues. The foam also has a channel ready for wiring which I do recognise as otherwise having the potential to be quite messy in this frame.
I also installed a CAT bubble trap, which with only a minor amount of dremeling found it's home in a tidy position. At the moment I'm thinking to offset the weight on the otherside with the fuel pump although that decision is not yet final.
After putting down a list of all of the other components that need to be installed, I can see that the real challenge in this kit is mounting everything so that it is not in the direct path of the air inlet. To that point I will need to put a couple of side mounting plates on the inside so minor fabrication is on the way...
Just by way of an update, over the weekend I tidied up some tail wiring, ceramic painted the blast area around the back of the turbine exit, and also spent some time getting my tanks installed. I used BVM fittings and felt clunks in the tanks themselves including a nice set of alloy collars I picked up at Jetpower last year. The manual says to secure the tanks by gluing them in, however I wanted to make mine removable for maintenance purposes so this introduced a new set of complexities....
In the end, I glued down some foam as a base for the tanks, setup quality hook and look against the side wall of the plane, and also came up with a velcro strap system in order to hold them firmly in position. They're gripped on a few sides so I don't anticipate any issues. The foam also has a channel ready for wiring which I do recognise as otherwise having the potential to be quite messy in this frame.
I also installed a CAT bubble trap, which with only a minor amount of dremeling found it's home in a tidy position. At the moment I'm thinking to offset the weight on the otherside with the fuel pump although that decision is not yet final.
After putting down a list of all of the other components that need to be installed, I can see that the real challenge in this kit is mounting everything so that it is not in the direct path of the air inlet. To that point I will need to put a couple of side mounting plates on the inside so minor fabrication is on the way...
03-02-2015, 06:56 PM
#1125
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Good idea, not gluing the tanks in. I filled mine with too much pressure, getting ready to maiden and cracked a tank. That grounded me for a while! When I cut the glue, I did even more damage to them. They are now held in with jet foam, basically just wedged in place and this works fine. I also made mounts that placed most gear on the fuselage sides, which thankfully prevented additional damage when I broke my tanks. I believe that I detailed all of this earlier in this forum. Good luck, mine flies great, imo...first turbine!
