Freewing 80mm F-5E Tiger II

[MKreun]

How fast were you going before rotation?.

I was posting another reply at the same time you posted your question that answers this. To paraphrase. It didn't pop on it's own and I didn't have to yank it off. Rotation was smooth. The roll didn't present itself until the wing began to produce lift. I should have added for clarity, both flights were towards the front of the CG envelope but on the first flight the battery shifted as I had to climb rapidly to avoid injuries and CG moved well aft of the limit with ironically is what allowed it to flat spin down to safety. To answer another way. The wing wasn't stalled, speed was high, AOA was low until I had to climb over the pits/people/cars. That exacerbated the problem but was not the cause. In the post crash discussion, no one felt that was an issue. My buddy who built his along with mine didn't even suggest it. He has no problem sharing his opinion or protecting my feelings. I'm assuming it was my rigging but we built them side by side. One flew, one was uncontrollable.

[JP-4203]

well understood, now would be interesting to compare both your and your friend's models side by side to check whether there were indeed some physical distortions regarding wing/elevator positions that might have caused a systematic asymmetric wing lift or roll force to the right. But I guess post-crash rather difficult to proceed?... BTW, out of curiosity, were you flying with a 5000 mAh (rather heavy) or lighter battery?

If I were you, I'd give it another try with a new F5 kit and 4000 battery - instead of an outside dinner with family 😁😁...

[gooniac33]

I was posting another reply at the same time you posted your question that answers this. To paraphrase. It didn't pop on it's own and I didn't have to yank it off. Rotation was smooth. The roll didn't present itself until the wing began to produce lift. I should have added for clarity, both flights were towards the front of the CG envelope but on the first flight the battery shifted as I had to climb rapidly to avoid injuries and CG moved well aft of the limit with ironically is what allowed it to flat spin down to safety. To answer another way. The wing wasn't stalled, speed was high, AOA was low until I had to climb over the pits/people/cars. That exacerbated the problem but was not the cause. In the post crash discussion, no one felt that was an issue. My buddy who built his along with mine didn't even suggest it. He has no problem sharing his opinion or protecting my feelings. I'm assuming it was my rigging but we built them side by side. One flew, one was uncontrollable.

nothing harder than flying a plane that is out of trim... That's what it sounds like to me. And also keep in mind that I have noticed the nose gear door causing all kinds of issues on mine after not having one in place for a while. It causes the plane to yaw right, pitch down and roll right as well. I set up flight modes to combat it but eventually just stopped using the nose gear door. Another thing to note is that this plane is very touchy with elevator throw. it is really easy to get it in to an accelerated stall without even really knowing what you have done! It will just kinda go limp and not respond to controls but the speed will make you think that something else is wrong when its really just a stall. Even with the high performance inrunners you need to let the plane pick up some speed and not use too much elevator on take off or risk getting into trouble. That is my take and hopefully it helps some.

[MKreun]

well understood, now would be interesting to compare both your and your friend's models side by side to check whether there were indeed some physical distortions regarding wing/elevator positions that might have caused a systematic asymmetric wing lift or roll force to the right. But I guess post-crash rather difficult to proceed?... BTW, out of curiosity, were you flying with a 5000 mAh (rather heavy) or lighter battery?

If I were you, I'd give it another try with a new F5 kit and 4000 battery - instead of an outside dinner with family 😁😁...

The day we did the first maiden, they were literally sitting side by side. Nothing was obvious. First flight was on an Admiral 4000 I borrowed. Second was on a 6000.

Gooniac,

nothing harder than flying a plane that is out of trim.

I agree. I didn't even get the chance to trim. The whole second flight was 3-5 seconds. In addition I was using full aileron to even slow the roll.

I have noticed the nose gear door causing all kinds of issues

I read this in one of your previous posts. I've experienced this in a DA-42 flying full scale. I was able to suck up the gear on the second flight and it didn't seem to change the flight characteristics. If I repair it, I'll fly without.

Another thing to note is that this plane is very touchy with elevator throw. it is really easy to get it in to an accelerated stall without even really knowing what you have done!

I had also previously read your notes regarding this. Second flight I did on low rates specifically to address this. My initial rotation was slow, smooth pitch up. 5-10 deg. I induced a stall in my maneuvering to avoid injury but the initial roll was not caused by a stall. I've been a pilot for 22 years, professionally for 13, I currently fly jets. I've flown aerobatics, practice accelerated stalls, I used to teach accelerated stalls. Not to say all of that translates to RC skill sets, but I've also flown many hours on the sims, specifically with training in mind, and also fly quad copters. I was doing aerobatics on my FW L-39 on the second flight flying RC jets. (I've since crashed goofing around and oh well, part of the hobby.) I openly seek critique and constructive criticism. If it was me causing an accelerated stall on rotation I would happily own that. I just want to have a better understanding of what happened. If I fix this up I wouldn't want to even attempt to fly it again b/c I still don't have a clue what happened. I would expect the same thing to occur at this point.

Thanks for all of your contribution to this thread. It's been very helpful to watch your videos.

[gooniac33]

The day we did the first maiden, they were literally sitting side by side. Nothing was obvious. First flight was on an Admiral 4000 I borrowed. Second was on a 6000.

Gooniac,



I agree. I didn't even get the chance to trim. The whole second flight was 3-5 seconds. In addition I was using full aileron to even slow the roll.



I read this in one of your previous posts. I've experienced this in a DA-42 flying full scale. I was able to suck up the gear on the second flight and it didn't seem to change the flight characteristics. If I repair it, I'll fly without.



I had also previously read your notes regarding this. Second flight I did on low rates specifically to address this. My initial rotation was slow, smooth pitch up. 5-10 deg. I induced a stall in my maneuvering to avoid injury but the initial roll was not caused by a stall. I've been a pilot for 22 years, professionally for 13, I currently fly jets. I've flown aerobatics, practice accelerated stalls, I used to teach accelerated stalls. Not to say all of that translates to RC skill sets, but I've also flown many hours on the sims, specifically with training in mind, and also fly quad copters. I was doing aerobatics on my FW L-39 on the second flight flying RC jets. (I've since crashed goofing around and oh well, part of the hobby.) I openly seek critique and constructive criticism. If it was me causing an accelerated stall on rotation I would happily own that. I just want to have a better understanding of what happened. If I fix this up I wouldn't want to even attempt to fly it again b/c I still don't have a clue what happened. I would expect the same thing to occur at this point.

Thanks for all of your contribution to this thread. It's been very helpful to watch your videos.

I just noticed something... Your second battery was a 6000....most likely that is the issue in your case The stock plane does not do well with weight and will fly horrible with most of the time being near uncontrollable. That makes sense now that I am reading it.

I also appreciate that you are so open to being critiqued! I am the same but so many people tend to not admit any wrong doing... I appreciate your experience in the full scale world and thanks for the kind words about mine as well! Keep flying!! Get that thing in the air and stay in the 4000-4500mah battery size to prevent it from flying horribly...

[MKreun]

I just noticed something... Your second battery was a 6000....most likely that is the issue in your case The stock plane does not do well with weight and will fly horrible with most of the time being near uncontrollable. That makes sense now that I am reading it.

I think it might be contributory but not causal, the flights were nearly identical. The roll existed on both. The first was with an Admiral 4000. Even that required full aileron to stop the roll. I had more control but I also had high rates. I used a Zeee 6000 50c that weighs about 840g. If you took a GPS track of both flights for the first 5 seconds they would be nearly identical. The controllability difference seemed to be due to the rates more than the weight.

[deadbug]

I just noticed something... Your second battery was a 6000....most likely that is the issue in your case The stock plane does not do well with weight and will fly horrible with most of the time being near uncontrollable. That makes sense now that I am reading it....
.

Just another data point regarding battery weight and this airplane:
I fly 5300mah and 6000mah batteries all the time in mine. Batt weight is 700grams for the 5300 and 825 for the 6000...no problems or horrible flying characteristics noted. CG is identical and measured exactly for each with the batteries placed appropriately for the identical CG. The only difference I notice is there is less flare and a slightly higher sink rate for the heavier battery with similar approach speeds.
DB

NOTE: This is with the FMS Platinum PRO V2 2100kv....but I also flew identical batts in the FMS 2000kv inrunner. But this wouldn't affect inflight characteristics...obviously takeoff is enhanced though. Takes off like a rocket ;-)

[gooniac33]

Just another data point regarding battery weight and this airplane:
I fly 5300mah and 6000mah batteries all the time in mine. Batt weight is 700grams for the 5300 and 825 for the 6000...no problems or horrible flying characteristics noted. CG is identical and measured exactly for each with the batteries placed appropriately for the identical CG. The only difference I notice is there is less flare and a slightly higher sink rate for the heavier battery with similar approach speeds.
DB

NOTE: This is with the FMS Platinum PRO V2 2100kv....but I also flew identical batts in the FMS 2000kv inrunner. But this wouldn't affect inflight characteristics...obviously takeoff is enhanced though. Takes off like a rocket ;-)

With the lighter more potent fans there isn't an issue with the weight. I was speaking of a stock powered outrunner. And yes with the FMS fans the plane is a rocket! I can go vertical as far as I can see from take off with the 2100kv set up...

[Phantom]

I flew mine on twin 4200's in parallel for 2 years, hobbystars, 8400mah total on stock power, no issues at all.

[MKreun]

So over the past few weeks I've been watching my buddy fly his F5 and increase his comfort in the flight envelope while I rebuilt my pile of confetti. Lots of foam tac, epoxy, and a few servos later it was ready to remained today. I added a Hobby Eagle Gyro after my buddy had success adding one to his. I had him fly the maiden and it was a resounding success. He said it flew just like his despite a few, uh, "aerodynamic deficiencies". In retrospect I agree with Gooniac's conclusion the a stall was the cause due to premature rotation/aft CG aided by the runway conditions. Although the CG was set to book the elevator had more than enough deflection to get airborne well before the wing was ready. In subsequent flights I pinned the nose the ground with down elevator until I used up about 3/4 of the runway and was well into flying speed. So much fun and flies like a dream now the kinks are worked out! Love the way it sounds as it goes ripping by. Also, other club member reported the flaps blanking out the elevator so we're running our landing flaps at about 35deg. Thanks again to everyone who chimed in with their experiences to help sort things out.

[gooniac33]

I flew mine on twin 4200's in parallel for 2 years, hobbystars, 8400mah total on stock power, no issues at all.

yeah its fine! You have gotten used to it and when you do the plane flies just fine. Once you change out the fans and see what it can do when its lighter... then you see how much you had been struggling and didn't even realize it. Thats how it was for my buddy and I once we swapped out the fans! It is night and day!

[Phantom]

I flew it with one 4200mah and 2 in parallel. You are correct about the change in performance with the single pack, albeit on stock power. It was just nice to stay up for 5 plus minutes.

Gooniac I have FMS fans in my 90mm F-16 and F-4 as well as an FMS fan in my 80mm F-86, so I am also a fan of FMS 's lighter weight, more thrust, and better efficiency resulting in longer flight times. Just never thought the F-5 warranted the additional cost of a swap, I also fly my approach to final nose down with 85° of barndoor flaps

[DForbes]

Does anyone know if there is a 3D printed nose out there available somewhere? Smashed the plastic piece and Motion is out of stock.

[Ron1950]

i need a longer nose strut for my vulcan can anyone measure the f5 nose strut from axel to steering arm? thanks

[gooniac33]

Because I was inverted....:

[bps]

Getting close to the maiden flight. I decided to attach the nose gear door and eliminate the possible issues that others have reported. Also added a 1/8” ply floor in the hopes that this provides a more rigid nose/fuse connection. Also gives me a mount for moving battery further back. Just waiting on replacement main gear mounts from Motion. The ones that came with the kit were broken. Comforting to have a supplier that has great customer service. Thanks Motion!

[406PIlot]

bps looking really good! Can't wait to hear how the maiden goes! Good luck.

[gooniac33]

Getting close to the maiden flight. I decided to attach the nose gear door and eliminate the possible issues that others have reported. Also added a 1/8” ply floor in the hopes that this provides a more rigid nose/fuse connection. Also gives me a mount for moving battery further back. Just waiting on replacement main gear mounts from Motion. The ones that came with the kit were broken. Comforting to have a supplier that has great customer service. Thanks Motion!

I like that idea!! I may need to do the same sorta thing with mine!!

[bps]

Struggling with battery weights and CG. My 5amp battery weights in at 764 grams and is shoved way back under the turtle deck. The light 3.3 amp battery (500 grams) is easier to put in the battery bay. Looks like the sweet spot for battery weight is maybe 640 grams. Guess I'm paying for that long nose! I 3D printed a battery tray and supports to place the receiver just under the rear turtle deck. Also found that 2" Dubro Super Light wheels fit inside the wheel wells on the mains with no foam removed. I used one of the main wheels and put it on the nose gear. Took just a bit of shaping on the foam wheel to make it fit. 3D printed exhaust nozzles and some strobe lighting finish up the modifications. I was concerned with the tree lines that surround our flying site I would loose this plane. Camo works I've heard!

[CAracer]

Just finished my maiden. All went well. Surprisingly, the Tiger required no trimming. The fuselage is a littlie flexible, upon landing, the canopy comes loose or completely pops off. I had to add some magnets to the canopy to keep it secure. It's a great sounding plane and a great flyer.