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Redshift; Used Purchase
- Thread starter Konrad
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- aeroic f3f redshift slope racing
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Konrad
Very Strong User
That was fun! I have to admit that I was dead last of those that had flown an F3F race. I blame the fact that I didn’t have adequate ballast. And I allowed racing to interfere with my flight testing. (That’s my story and I’m sticking to it)!
I was getting a bit more attention than usual as I think this was the first Redshift most had seen flying.
There’s nothing like racing to show the errors of one’s set up.
While I think I’m not over flying the bases too much as witnessed by the may cuts. I am having a problem maintaining my energy.
My set up was CG 95mm to 96mm
Elevator was 7mm
Rudder was 7mm
Total V tail was 14mm up and 15mm down
Ailerons 17mm up and 10mm down
Aileron to flap mix 4mm up and 5.5mm down (Not enough and the differential is reversed)
Snap flap 2.5mm
Aileron to rudder mix 18 (units unknown)
What I noticed was that my aileron roll rate was rather slow. This forced me to remove all the differential adjustment in Mike Shellim’s templet leaving only the mechanical differential. You might notice that I’ve improperly rigged the flaps as ailerons with more down than up. On the hill I had to add some aileron to rudder mix to try to tame the adverse yaw.
I did suffer one high speed stall. I’m happy to report that unloading the wing the air reattached rather quickly with no resulting spin.
I have to admit that the small tip chord scared me when I first saw the Redshift. But the wing is very forgiving.
The only other high aspect ratio glider was a Fossa Lift. She was turning real well, better than I was turning the Redshift, and making noise doing it. My Redshift was dead silent in the very dry inland air, that or I’m deaf
The bad news is that I tore off a flap. The good news is that I can say the Kevlar used was properly biased as to allow all the kevlar threads to cross the hinge line. With the skills I’ve learned repairing the V-tail hinges the flaps should be a doable repair.
All the best,
Konrad
I was getting a bit more attention than usual as I think this was the first Redshift most had seen flying.
There’s nothing like racing to show the errors of one’s set up.
While I think I’m not over flying the bases too much as witnessed by the may cuts. I am having a problem maintaining my energy.
My set up was CG 95mm to 96mm
Elevator was 7mm
Rudder was 7mm
Total V tail was 14mm up and 15mm down
Ailerons 17mm up and 10mm down
Aileron to flap mix 4mm up and 5.5mm down (Not enough and the differential is reversed)
Snap flap 2.5mm
Aileron to rudder mix 18 (units unknown)
What I noticed was that my aileron roll rate was rather slow. This forced me to remove all the differential adjustment in Mike Shellim’s templet leaving only the mechanical differential. You might notice that I’ve improperly rigged the flaps as ailerons with more down than up. On the hill I had to add some aileron to rudder mix to try to tame the adverse yaw.
I did suffer one high speed stall. I’m happy to report that unloading the wing the air reattached rather quickly with no resulting spin.
I have to admit that the small tip chord scared me when I first saw the Redshift. But the wing is very forgiving.
The only other high aspect ratio glider was a Fossa Lift. She was turning real well, better than I was turning the Redshift, and making noise doing it. My Redshift was dead silent in the very dry inland air, that or I’m deaf
The bad news is that I tore off a flap. The good news is that I can say the Kevlar used was properly biased as to allow all the kevlar threads to cross the hinge line. With the skills I’ve learned repairing the V-tail hinges the flaps should be a doable repair.
All the best,
Konrad
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Konrad
Very Strong User
Well that worked better than it should. The process for repairing the torn Kevlar hinge I mentioned earlier (Post # 88) has worked great on at least 4 occasions. Dare I say better than new. The live hinge from most OEM have a rather stiff hard epoxy in the matrix (laminating epoxy). With my repair I'm using a much more flexible epoxy (adhesive). I think the laminating epoxy will leave very sharp shards in the hinge line as it is flexed. I hope that the adhesive epoxy will result in duller particles less likely to cut the Kevlar fibers.
These repaired hinges give me more confidence than silicone repaired hinges. And I think will take a lot less maintenance.
Now I have to work on Mike Shellim's templet to extract the potential performance trapped in the airframe. (Have I told you all, I hate programing)!
All the best,
Konrad
These repaired hinges give me more confidence than silicone repaired hinges. And I think will take a lot less maintenance.
Now I have to work on Mike Shellim's templet to extract the potential performance trapped in the airframe. (Have I told you all, I hate programing)!
All the best,
Konrad
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Konrad
Very Strong User
I fear today I may have lost my Redshift.
Truth be told it was pilot error in that I was flying in 40+ mph winds with gusts over 60mph. All without the benefit of ballast! It was that last part that put the Redshift at risk. I was landing at the SloT and was trying to make headway against the wind . I was doing fine until a gust pushed me towards no-mans land (the back side of the ridge). Then the gust stopped and all I could do was fly into the back side of the ridge. The impact was hard but as I didn’t have any ballast on board I thought I might have gotten away with it (lower mass means less energy). I’m happy to report there was no cartwheeling. When I got the the site I was a bit surprised to see that most of the OEM live hinges had torn off. This is an indication of much more energy than I expected. But the odd thing was that my Kevlar repaired hinges all held. (Hum?)
Then I saw the grotesque sight of a twisted and partially torn out wing joiner box. (This is the damage that might be fatal).
I was amused that the nose cone sphere was gone! There were some bits of it. It actually looked like there had been red easter egg at the crash site. I was shocked that the OEM would have tried to make some part of the model (The one most likely to impact the ground) out of a thin shell of non reinforced epoxy. Just dumb!
I’ve pop out most of the distortion (I used a hammer to drive back the web). As is my practice I'll wait until the morning to make my assessment with the help of a bore scope.
Truth be told it was pilot error in that I was flying in 40+ mph winds with gusts over 60mph. All without the benefit of ballast! It was that last part that put the Redshift at risk. I was landing at the SloT and was trying to make headway against the wind . I was doing fine until a gust pushed me towards no-mans land (the back side of the ridge). Then the gust stopped and all I could do was fly into the back side of the ridge. The impact was hard but as I didn’t have any ballast on board I thought I might have gotten away with it (lower mass means less energy). I’m happy to report there was no cartwheeling. When I got the the site I was a bit surprised to see that most of the OEM live hinges had torn off. This is an indication of much more energy than I expected. But the odd thing was that my Kevlar repaired hinges all held. (Hum?)
Then I saw the grotesque sight of a twisted and partially torn out wing joiner box. (This is the damage that might be fatal).
I was amused that the nose cone sphere was gone! There were some bits of it. It actually looked like there had been red easter egg at the crash site. I was shocked that the OEM would have tried to make some part of the model (The one most likely to impact the ground) out of a thin shell of non reinforced epoxy. Just dumb!
I’ve pop out most of the distortion (I used a hammer to drive back the web). As is my practice I'll wait until the morning to make my assessment with the help of a bore scope.
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Konrad
Very Strong User
WOW, she might live!
Looking at the insides with a bore scope. I'm finding very little fiber distress. What little I do see has been in the horizontal plane. (Direction of force from the crash) This means that most of the structure dealing with the bending moments in flight is still intact just debonded from each other.
Also looking at the fuselage at the wing fillet I can report that this area performed admirably. I see no stress marks in that area. Nor do I see any damage around the ballast loading port. I do see some stess crack in the joiner opening and some chipped epoxy at the front edge of the opening. (Truth be told these chips where there when I bought the Redshift, just not as large as they are now. I think these are cosmetic).
Much to my surprise I think the worst part of this repair will be re-hinging all the control surfaces.
Ok, the worst part will be cleaning off the bench to make room for the repair!
All the best,
Konrad
Looking at the insides with a bore scope. I'm finding very little fiber distress. What little I do see has been in the horizontal plane. (Direction of force from the crash) This means that most of the structure dealing with the bending moments in flight is still intact just debonded from each other.
Also looking at the fuselage at the wing fillet I can report that this area performed admirably. I see no stress marks in that area. Nor do I see any damage around the ballast loading port. I do see some stess crack in the joiner opening and some chipped epoxy at the front edge of the opening. (Truth be told these chips where there when I bought the Redshift, just not as large as they are now. I think these are cosmetic).
Much to my surprise I think the worst part of this repair will be re-hinging all the control surfaces.
Ok, the worst part will be cleaning off the bench to make room for the repair!
All the best,
Konrad
Konrad
Very Strong User
I'm wondering if my heavy tip was because the wing root side was light on bonding epoxy. Hum, but this was the heavy wing
forum.alofthobbies.com
I'm finding it a bit odd that all the control surfaces have damaged live hinges. But that none of the servos are stripped. This might be a nod towards the use of bearing supported servo trays. This really is surprising to me particularly with the small gears in the X0-8
Redshift; Used Purchase
slightly off-top I cured the damn landing approach from 14.June We will see if it holds, fuse ballast tube is now out of order @Konrad flying stuff from slot, wrecker or the coast?? Are those 4x4 carbon? Can you added carbon tow (cording) on top of the tray and under the snakes? And bond this...
forum.alofthobbies.com
I'm finding it a bit odd that all the control surfaces have damaged live hinges. But that none of the servos are stripped. This might be a nod towards the use of bearing supported servo trays. This really is surprising to me particularly with the small gears in the X0-8
Konrad
Very Strong User
I did find some more minor damage. I hope you can see where the end of the joiner punched into the aft vertical joiner box web as the wing swung forward. I also see some damage In the aft corners of the wing joiner box.
I see no damage to the inner skins or spar caps. Nor do I see any epoxy fillets at the sine wave and cap junction. Or at the spar cap to wing skin junction. This indicates a very dry assembly of the sub structure.
This may have been a double edged sword as the poor bonding of the substructure allowed the parts to separate early* but not induce much skin damage.
*The damage shown was from impact not flight loads. I have no way of knowing what forces were involved.
All the best,
Konrad
I see no damage to the inner skins or spar caps. Nor do I see any epoxy fillets at the sine wave and cap junction. Or at the spar cap to wing skin junction. This indicates a very dry assembly of the sub structure.
This may have been a double edged sword as the poor bonding of the substructure allowed the parts to separate early* but not induce much skin damage.
*The damage shown was from impact not flight loads. I have no way of knowing what forces were involved.
All the best,
Konrad
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Doc J
Very Strong User
I have now seen this kind of thing many times from my old OEM.
BUT IT STILL PISSES ME OFF!
BUGGER: Its just as damn easy to do it well and correctly as it is to try to cut corners by this type of thing.
Fire Trucking idiot!
Happily the new guy is all too aware of this kind of thing as he builds a lot of DS models.
I'm happy that Konrad is getting into this so deeply, but really sorry that he had to.
Doc.
BUT IT STILL PISSES ME OFF!
BUGGER: Its just as damn easy to do it well and correctly as it is to try to cut corners by this type of thing.
Fire Trucking idiot!
Happily the new guy is all too aware of this kind of thing as he builds a lot of DS models.
I'm happy that Konrad is getting into this so deeply, but really sorry that he had to.
Doc.
Konrad
Very Strong User
As I recall (somewhere on this forum) the new guy (Frank) did some destructive testing where he sectioned the model to show how the layups and bonding of subcomponents looked.
Now the problem for an OEM is that we want light models. So this puts a lot of pressure to not use too much epoxy. But what we see here is a gross swing towards not using enough glue. While I think the old guy (Zohe?) did a much better job with this Redshift than what we see in my 2 RCRCM Stregas, there are a lot of areas where the craftsmanship, and dare I say, materials are inadequate.
If there is a knock against the new guy is that his ships are a bit heavy. This is not a problem for most slope ships. If one is going to mis-perfection it is best to use a bit too much epoxy than end up not using enough!
Yes, I like failure analysis. I like to understand how a structure performs. I also like repair development.
All the best,
Konrad
Now the problem for an OEM is that we want light models. So this puts a lot of pressure to not use too much epoxy. But what we see here is a gross swing towards not using enough glue. While I think the old guy (Zohe?) did a much better job with this Redshift than what we see in my 2 RCRCM Stregas, there are a lot of areas where the craftsmanship, and dare I say, materials are inadequate.
If there is a knock against the new guy is that his ships are a bit heavy. This is not a problem for most slope ships. If one is going to mis-perfection it is best to use a bit too much epoxy than end up not using enough!
Yes, I like failure analysis. I like to understand how a structure performs. I also like repair development.
All the best,
Konrad
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Konrad
Very Strong User
Well, I think I fixed the loose wing box. The trick was being willing to hack at the wing root to allow epoxy to flow down the outside corners of the wing box to bond to the skins and spar caps. I also saturated the damaged fibers shown earlier.
Key to being able to do this was the making of spade drills from music wire to go down the length of the wing box.
I started with a distorted wing to open up any cracks and delamination. I came in from the servo opening for this. Then I popped the wing back into shape. Ran epoxy in the access holes. Clamped and taped everything in place. Stepped back and hoped!
As of now there is a bit of distortion at the root from not making proper tooling and allowing a clamp to distort the skin.
The wing box has passed its first stress test in that the wing can hold up to 60 lbs. I'll wait for full cure before doing a 10G test.
So the next step is to fix all the live hinges!
Key to being able to do this was the making of spade drills from music wire to go down the length of the wing box.
I started with a distorted wing to open up any cracks and delamination. I came in from the servo opening for this. Then I popped the wing back into shape. Ran epoxy in the access holes. Clamped and taped everything in place. Stepped back and hoped!
As of now there is a bit of distortion at the root from not making proper tooling and allowing a clamp to distort the skin.
The wing box has passed its first stress test in that the wing can hold up to 60 lbs. I'll wait for full cure before doing a 10G test.
So the next step is to fix all the live hinges!
Konrad
Very Strong User
Yes, very easy to fix. With a disposable pipet and some heat shrink tubing I was able apply epoxy down all 8 corners of the webs. The web failed as the joiner box acts like a lever trying to spread the spar caps apart.
This is a limitation of the this type of construction in that there is no fiber trying the keep the spar caps attached to the sine wave web. This is no place to skimp on the adhesive or the quality of the adhesive. This limitation of the fiber (lack of) is why it is not recommended that these be DS'd
This is a limitation of the this type of construction in that there is no fiber trying the keep the spar caps attached to the sine wave web. This is no place to skimp on the adhesive or the quality of the adhesive. This limitation of the fiber (lack of) is why it is not recommended that these be DS'd
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Konrad
Very Strong User
I've been trying to figure out how to spin this. On one hand I can use this to show how much strength I added to the nose of the Redshift. Or admit that this is a strong indication of just how hard I hit the side of the hill.
What I'm showing is a compression crack from the impact with the side of the hill. Nothing hit the tail cone. This damage is from shock wave recoil/whipping flex of the tail boom. This really dose show that there was a lot more energy in the crash than I thought. I did see the impact and thought it didn't look that bad. But that all the hinges failed and I now see this compression damage the "G" loads had to be very high. All I can think of is that the steep slope of the hill effectively made the impact of the fuselage 90° to the ground little or no deflection (skip slide on the ground) also there is a high probability that at the site I was flying that I could have hit a rock just under the weeds.
I think I have to give credit to the IDS servo trays for not seeing any stripped servo gears.
The good new from this impact is that the nose held up great! Well, other than the slip on nose cone. The carbon ballast tube and support around the ballast loading window performed as expected.
Now I've had a failure with one of my hinge repairs. That is the an aileron doesn't line up with the wing. This really shouldn't be too surprising as I'm not making any tooling to perform these repairs. Now I have to admit that the only thing worse than the original damage is having to remove a failed repair and try again.
All the best,
Konrad
What I'm showing is a compression crack from the impact with the side of the hill. Nothing hit the tail cone. This damage is from shock wave recoil/whipping flex of the tail boom. This really dose show that there was a lot more energy in the crash than I thought. I did see the impact and thought it didn't look that bad. But that all the hinges failed and I now see this compression damage the "G" loads had to be very high. All I can think of is that the steep slope of the hill effectively made the impact of the fuselage 90° to the ground little or no deflection (skip slide on the ground) also there is a high probability that at the site I was flying that I could have hit a rock just under the weeds.
I think I have to give credit to the IDS servo trays for not seeing any stripped servo gears.
The good new from this impact is that the nose held up great! Well, other than the slip on nose cone. The carbon ballast tube and support around the ballast loading window performed as expected.
Now I've had a failure with one of my hinge repairs. That is the an aileron doesn't line up with the wing. This really shouldn't be too surprising as I'm not making any tooling to perform these repairs. Now I have to admit that the only thing worse than the original damage is having to remove a failed repair and try again.
All the best,
Konrad
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