Buffalo FX-79 Build - maiden/re-maiden crash, 3rd time lucky

[Benny_H88]

The way the arc tightened in on itself suggests to me the AP was interfering making things worse, either that or it was trimmed for a nose dive. i agree with what others have said about the ailerons requiring some added reflex

[CurryKitten]

Ok, time to give this another go.  Off to visit FBS on Saturday, and finger crossed the rain will hold off to give this and his new MFT a fly

[Sheldon Holy]

I'll bet 100 quid that this was not a stall. Generally when these things are launched there is a period where it's just using the momentum from the launch to stay in the air, the thrust from the motor builds up the speed and by the time the thing would be falling back to earth, it's got enough speed and is flying.

This is how the Harriers launched, when it left the ski jump they weren't flying fast enough to maintain altitude. The jump just placed them on a parabolic arc and by the time they would drop down, the speed was up and they were climbing away.

Incorrect thrust lines are also out of the question as the effect would be immediate upon launch. As I said above, immediately after launch the wings aren't doing all that much and so if the thrust lines are off, it'll flip over almost instantly. This has happened to me a few times when I've accidentally bent a motor mount on a wing and launched without realising.

All I can think of is what's been said before, a control input by something or other. How was your failsafe set?

[English Turbines]

Ok, time to give this another go.  Off to visit FBS on Saturday, and finger crossed the rain will hold off to give this and his new MFT a fly

Hi Wayne,....good luck m8, and please, please dont launch it again wearing goggles, you just cant see whats going on properly....What do I mean?...if the model is launched upwards at an angle (like last time) all you see in your goggles is sky, no perception at all of forward speed, or indeed if its even been launched?...hope that makes sense.....At least until you have the elevons trimmed, and I would set some more up on them, its easier to handle than not enough for sure.....:)

:vulture:

[highlander]

There wasn't a chance Wayne could have saved that first launch, everything happened too fast. I had a similar crash before I believe mine was caused by autopilot setting throttle to high on the powerful motor and the plane simply nosedived.

Good luck this time around, worth checking and rechecking everything a couple of times before launch.

[Brucey]

Good luck buddy!

[CurryKitten]

The plan this time is to give it a few unpowered glides.  It's not that heavy, and the wing area is massive, so it should be floaty.  If that's good then I will aim to power up after the throw and make sure it's ok LOS.  I'm an awful LOS flyer, but even I should be able to go 100m in a straight line and put it down again.

If it's not smashed up by this point, the goggles go on.

[Brucey]

Got a bungee you can try if you get really pissed off!
Sounds like a plan,  but I'd take off Los and switch to fpv as my Los flying is rubbish too!

[Jake Bullit]

As before get yourself on a hill or bank where the ground falls away in the direction of launch,a headwind will help,good firm chuck about 15 deg above horizontal and about 70% throttle,maybe a a couple of clicks of uptrim.

Good luck :)

[highlander]

Getting yourself on the bank or hill helps if you have a slight problem e.g. plane to heavy and lose height while gliding. In case of immediate nosedive it makes things worse as there is more height to fall from.

[Billy_boy_2010]

Getting yourself on the bank or hill helps if you have a slight problem e.g. plane to heavy and lose height while gliding. In case of immediate nosedive it makes things worse as there is more height to fall from.

I disagree- a nosedive at say 45 degrees towards the flat ground becomes a 25 degree nose dive towards a 20 degree downward slope- much better. The few extra feet of fall height is far outweighed by this.

Good luck Curry.

IMO

Keep all autopilots etc off

Set it up with the lightest battery combo possible.

Throw in long grass into the wind a few times.

Launch LOS. I'm a terrible LOS pilot but, unless the plane is extremely fast, you will be safer than fpv.

Have a friend click the trim while you just fly it straight. Having said that I find trim easier to do fpv provided she flies well enough to fpv it.

Set up dual rates on the tx. If it's way too twitchy on the higher rates switch to low.

Also why do some people always advocate launching on 70% throttle? Unless it's hugely powered and likely to torque itself into the ground (like a funjet!) full throttle can only make the launch easier imo.

Also maybe run and throw the plane while running? Gives you a few extra mph on launch.

[UAV Aviation]

Good luck 👍

[Brucey]

Getting yourself on the bank or hill helps if you have a slight problem e.g. plane to heavy and lose height while gliding. In case of immediate nosedive it makes things worse as there is more height to fall from.

I disagree- a nosedive at say 45 degrees towards the flat ground becomes a 25 degree nose dive towards a 20 degree downward slope- much better. The few extra feet of fall height is far outweighed by this.

Good luck Curry.

IMO

Keep all autopilots etc off

Set it up with the lightest battery combo possible.

Throw in long grass into the wind a few times.

Launch LOS. I'm a terrible LOS pilot but, unless the plane is extremely fast, you will be safer than fpv.

Have a friend click the trim while you just fly it straight. Having said that I find trim easier to do fpv provided she flies well enough to fpv it.

Set up dual rates on the tx. If it's way too twitchy on the higher rates switch to low.

Also why do some people always advocate launching on 70% throttle? Unless it's hugely powered and likely to torque itself into the ground (like a funjet!) full throttle can only make the launch easier imo.

Also maybe run and throw the plane while running? Gives you a few extra mph on launch.

I agree with what you say,  apart from running and throwing,  the extra coupe of mph will be wasted because of the poor throw you'll end up doing.

Good luck bud!

[iPeel]

Good luck Wayne! Remember, wings can sense anxiety and that's when they attack. Be brave and take charge, give it a firm chuck and tell it who's boss!

[FPVSteve]

Way too much overthinking in this thread.

Just give it some beans, chuck it at 45 degrees then get your hands on the sticks. It'll be fine, they usually are unless something is WAY off, and it won't be that bad - you're experienced enough now to have a rough idea of gear placement.