GRYPHON - build thread (sports/trainer 2m composite jet)
04-20-2014, 08:08 AM
#276
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OK back on the project following some time on pressing 'other' jobs.
Now the retracts from Electron have arrived and the legs from Jet-1A, who I have to say are very helpful indeed and offer a great service.
Having heard from a few the nose gear and mains mounting plates are a little weak I added and beefed up the nose gear mounting with some extra ply formers glues to the existing and Aeropxied in place, I also added some extra ply to the rails to add some thickness to them to help achieve a stronger frame.
The Electron nose retract has the built in steering coupling, its a nicely made unit but I was struggling to work out how to hook up a servo to it without having to use wire connections which I personally hate. The Gryphon has a servo plate already fitted just forward of the tank but I decided to try a more direct linked system. I cut a piece of FR4 to fit round the main retract body and use the mounting holes as a fixing point, the FR4 plate then extended away from the main unit to allow for a servo to be mounted on it a few inches away from the steering tiller. I connected the servo to the tiller with clevis links and made sure the hole positions for the servo arm matches those of the tiller arm to avoid issues. The unit seems strong and fits nicely inside the nose section, gives positive steering, no slop and no wires to get hung up.
The wing wheel well cut-outs were not centralised on one wing, I suspect the template used to cut these moved during the routing process. Looking at the tyre options from Jet-1A I wanted to use as large a wheel as was possible, three reasons, one its better for grass to have a bigger wheel, second the ones I have seen fitted to some Gryphon's just seem a little too small, and third as I want to try to fit our new e-brakes I needed to give myself as much room as possible in the wheel hub area. I chose 75mm diameter wheels and 147mm long legs which seemed about right.
I had a friend cut me a couple of ply jigs to re-cut the wheel cut-outs, these included an 85mm diameter wheel hole to allow for the new bigger 75mm unit. A Proxxon drill, small flanged bearing and cutter through its centre was used to run round the template and re-cut the new opening.
Nose wheel is now in, mains are awaiting some 8mm dowels to connect them to the retracts. I still need to strengthen the main retract plates before final gear fitment but should have this done during the next few days.
marcs
Now the retracts from Electron have arrived and the legs from Jet-1A, who I have to say are very helpful indeed and offer a great service.
Having heard from a few the nose gear and mains mounting plates are a little weak I added and beefed up the nose gear mounting with some extra ply formers glues to the existing and Aeropxied in place, I also added some extra ply to the rails to add some thickness to them to help achieve a stronger frame.
The Electron nose retract has the built in steering coupling, its a nicely made unit but I was struggling to work out how to hook up a servo to it without having to use wire connections which I personally hate. The Gryphon has a servo plate already fitted just forward of the tank but I decided to try a more direct linked system. I cut a piece of FR4 to fit round the main retract body and use the mounting holes as a fixing point, the FR4 plate then extended away from the main unit to allow for a servo to be mounted on it a few inches away from the steering tiller. I connected the servo to the tiller with clevis links and made sure the hole positions for the servo arm matches those of the tiller arm to avoid issues. The unit seems strong and fits nicely inside the nose section, gives positive steering, no slop and no wires to get hung up.
The wing wheel well cut-outs were not centralised on one wing, I suspect the template used to cut these moved during the routing process. Looking at the tyre options from Jet-1A I wanted to use as large a wheel as was possible, three reasons, one its better for grass to have a bigger wheel, second the ones I have seen fitted to some Gryphon's just seem a little too small, and third as I want to try to fit our new e-brakes I needed to give myself as much room as possible in the wheel hub area. I chose 75mm diameter wheels and 147mm long legs which seemed about right.
I had a friend cut me a couple of ply jigs to re-cut the wheel cut-outs, these included an 85mm diameter wheel hole to allow for the new bigger 75mm unit. A Proxxon drill, small flanged bearing and cutter through its centre was used to run round the template and re-cut the new opening.
Nose wheel is now in, mains are awaiting some 8mm dowels to connect them to the retracts. I still need to strengthen the main retract plates before final gear fitment but should have this done during the next few days.
marcs
This looks like the direction I'd like to go with steering. Does anyone know if this type arrangement is available pre manufactured for different gear?
10-02-2017, 09:57 AM
#277
I know this plane has been out for awhile, but I just acquired a used one and would appreciate if someone has a summary of the following:
Control throws - aileron, elevator:
Flap settings and throw for T/O and landing:
Looks like CG should be about 210 mm if I found that info correctly:
Just wanting to not have big surprises on the new to me maiden. Thanks in advance!
Control throws - aileron, elevator:
Flap settings and throw for T/O and landing:
Looks like CG should be about 210 mm if I found that info correctly:
Just wanting to not have big surprises on the new to me maiden. Thanks in advance!
10-03-2017, 05:41 PM
#279
the CG needs to be way further back than most is saying. Its way too nose heavy when the CG is in front of the spar. Mine is behind the spar. Thats the reason it wasn't well liked.. it was hard to rotate and slammed down during landing.. I am flying the crap out of mine, it rotates nicely, flies great and lands lightly.. I will measure the actual CG and let you know, but I would not let it go in front of the spar. ALL the fuel is forward of the CG, so balancing it empty the CG has to be way back empty
I acquired a used one too, and immediately took some battery weight out of the nose, moved it back where it would sit on its tail when its empty on fuel.. It drops down on the nose wheel when the main tank hits about 1/3 way full.
The throws recommend were too much for the elevator and aileron, and made it snappy and prone to accelerated stall with my CG back, so I reduced it. I am using about 3/4 inch.. Running a Cortex Pro with stock settings and 35% gain too.
I really like this plane.. I have but 25 flights on it, and haven't touched the CG after moving it back to sit on its tail when empty. When this one was built, they moved the motor forward, put a longer tailpipe in it, put the batteries in the nose and the air trap above the nose gear,.. basically everything forward.. I have a 3800 Life 3 cell and 2 small 2600 Lipos in the nose.. no additional weight. It will knife edge for a half mile, and do nice slow rolls. Mine has a rabbit 100 in it and 2 extra 16 ounce flat tanks under the main tank.. 7-8 min flights.
ALSO... I used about 40 degrees of flap and 3/8 inch of CROW.. The crow was a calculated guess, and it worked perfectly.. tail dropped and it set up nicely.. I watched a bunch of video and everyone was diving to the runway too flat with it, so I wanted it to drop the tail like a swept wing plane should.. ITs a very gentle plane in the pattern.. I started with 1/4 inch crow and went to 3/8 inch at full flap, and 1/8 inch at takeoff.
During your maiden, if you don't like the final flap setting put it in takeoff flaps and land it.. it will land fine..
I kinda went against the grain on this, but I think I went the right way with it.. It completely transformed it to a great everyday banger flying off the grass at my field.. Kinda surprised everyone how much better it flew than the old Evos we saw back when.
Its my new favorite plane..
I acquired a used one too, and immediately took some battery weight out of the nose, moved it back where it would sit on its tail when its empty on fuel.. It drops down on the nose wheel when the main tank hits about 1/3 way full.
The throws recommend were too much for the elevator and aileron, and made it snappy and prone to accelerated stall with my CG back, so I reduced it. I am using about 3/4 inch.. Running a Cortex Pro with stock settings and 35% gain too.
I really like this plane.. I have but 25 flights on it, and haven't touched the CG after moving it back to sit on its tail when empty. When this one was built, they moved the motor forward, put a longer tailpipe in it, put the batteries in the nose and the air trap above the nose gear,.. basically everything forward.. I have a 3800 Life 3 cell and 2 small 2600 Lipos in the nose.. no additional weight. It will knife edge for a half mile, and do nice slow rolls. Mine has a rabbit 100 in it and 2 extra 16 ounce flat tanks under the main tank.. 7-8 min flights.
ALSO... I used about 40 degrees of flap and 3/8 inch of CROW.. The crow was a calculated guess, and it worked perfectly.. tail dropped and it set up nicely.. I watched a bunch of video and everyone was diving to the runway too flat with it, so I wanted it to drop the tail like a swept wing plane should.. ITs a very gentle plane in the pattern.. I started with 1/4 inch crow and went to 3/8 inch at full flap, and 1/8 inch at takeoff.
During your maiden, if you don't like the final flap setting put it in takeoff flaps and land it.. it will land fine..
I kinda went against the grain on this, but I think I went the right way with it.. It completely transformed it to a great everyday banger flying off the grass at my field.. Kinda surprised everyone how much better it flew than the old Evos we saw back when.
Its my new favorite plane..
Last edited by gooseF22; 10-03-2017 at 05:51 PM.
10-03-2017, 07:18 PM
#280
Thanks Goose! I was wondering about the CG as mine too has the ECU, 2 lipo RX packs AND the retract battery in the nose. The UAT is in front of the main tank.
I noticed you fly JETI, wondering if you would be willing to discuss some flight modes and other details on this plane over the phone. I'll PM you my info.
Thanks!
I noticed you fly JETI, wondering if you would be willing to discuss some flight modes and other details on this plane over the phone. I'll PM you my info.
Thanks!
10-03-2017, 10:09 PM
#282
Join Date: Mar 2004
Location: ferrara, ITALY
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I was the first in test evo version from gryphon ...the model showed in the pic's was first evo model to flight,..
my choice was 1cm in front to spar with full UAT and main tank not empty (end flight configuration) in order to have very precise flight an not nervous plane..
this configurantion need to apply travel on elevator during landing because mobile surface in the tail is little.
i recommend to fly with cg 1cm in front.. and without winglets
the plane is very good for precise aerobatic flight... max 100n engine is recommended
my choice was 1cm in front to spar with full UAT and main tank not empty (end flight configuration) in order to have very precise flight an not nervous plane..
this configurantion need to apply travel on elevator during landing because mobile surface in the tail is little.
i recommend to fly with cg 1cm in front.. and without winglets
the plane is very good for precise aerobatic flight... max 100n engine is recommended
Last edited by chrigui; 10-03-2017 at 10:34 PM.
10-04-2017, 09:31 AM
#283
Join Date: Aug 2010
Location: , , UNITED KINGDOM
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I’m sure mine was about 2cm behind the wing tube. It would be massively nose heavy if cg was in front of tube.
Loved my Gryphon, flew sweet and stable. Only change I would reinforce the retract mounts in the wing as I think the design is weak.
Simon
Loved my Gryphon, flew sweet and stable. Only change I would reinforce the retract mounts in the wing as I think the design is weak.
Simon
10-04-2017, 12:48 PM
#285
Agree. Especially with trailing link gear, it flopped on the nose hard during the maiden according to the guy that flew it. I picked it up it had flown a couple times.. My engine is stuffed right up in the intake, and it has a Tam Pipe thats longer.
10-04-2017, 12:51 PM
#286
I was the first in test evo version from gryphon ...the model showed in the pic's was first evo model to flight,..
my choice was 1cm in front to spar with full UAT and main tank not empty (end flight configuration) in order to have very precise flight an not nervous plane..
this configurantion need to apply travel on elevator during landing because mobile surface in the tail is little.
i recommend to fly with cg 1cm in front.. and without winglets
the plane is very good for precise aerobatic flight... max 100n engine is recommended
my choice was 1cm in front to spar with full UAT and main tank not empty (end flight configuration) in order to have very precise flight an not nervous plane..
this configurantion need to apply travel on elevator during landing because mobile surface in the tail is little.
i recommend to fly with cg 1cm in front.. and without winglets
the plane is very good for precise aerobatic flight... max 100n engine is recommended
10-05-2017, 05:21 AM
#288
Join Date: Mar 2004
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after remove winglets turning left or right was much more precise and fast
in landing the use of wiglets help stability ...
you can try to flight with or without....to do right choice...(only 2 screw each winglet)
Last edited by chrigui; 10-05-2017 at 05:24 AM.
10-14-2017, 08:56 AM
#289
Hi guys,
My Evo is nearing completion and what puzzles me, there is no wing-fuselage connection. My first jet, Xcalibur, has clamps in the wings that are tightened around the carbon spar with bolds that are inserted in the upper wing skin. My Evo only has a carbon spar and that's all.... What am I missing, parts or insight?? All I can think of is they forgot to drill holes in the wing skin were the clamps are....
Thx, Marco
My Evo is nearing completion and what puzzles me, there is no wing-fuselage connection. My first jet, Xcalibur, has clamps in the wings that are tightened around the carbon spar with bolds that are inserted in the upper wing skin. My Evo only has a carbon spar and that's all.... What am I missing, parts or insight?? All I can think of is they forgot to drill holes in the wing skin were the clamps are....
Thx, Marco
10-14-2017, 09:01 AM
#290
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Wings are retained by two small M3 bolts in the wheel wells. Once you have the wings on, drop the wheels to get access. They mate up with two threaded holes on the wing root on the fuselage.
Simon
Simon
