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First steps, or crashes...

#1
So I bought myself a HK Tuff Trainer as a first plane. What could go wrong right? Well after I bought the plane I found a bunch of threads about the problems with the machine. Well I have it now so I will persist with it for the time being. So I shall detail my experiences with it here.

First up the plane comes with a stupid little battery connector on the ESC. The recommended batteries come with XT60 connectors which to my mind seem far superior. So it was another order, and another lot of postage charges to get connectors. While at it I ordered a couple of extra batteries and a couple of spare props.

Next up I built the plane as per the instructions but with enlarging the battery bay forward to be large enough to take a 1300mAh battery. Because reports on the problems with the machine varied I decided to try a flight to see what it did before trying any of the suggested mods I found online. Having successfully got the thing into the air my first flight lasted about 10 seconds before the most commonly reported fault came to light. The plane banked right and nose dived into the ground. This broke the prop saved o-ring (no big deal) and cracked the foam from the rear of the battery compartment up toward the windscreen. The whole front was very near to coming adrift. Hmm, a little disappointing.

So, to the repairs. I have inserted BBQ skewers from above the firewall, through the battery bay and into the main body and glued them in. This should reinforce this weak area nicely. Next I have modified the motor mount to remove the insane down thrust it has as standard. Now I'm trying to decide whether to give it the often recommended 3 degrees right thrust. I also need to sort out a binding problem with the elevator linkage. It seems that the speed link is binding in part of it's downward movement.

Then I think it will be time to try a second flight.

Another recommendation I have seen is to remove the dihedral. I'd rather keep it at this stage it the thing will fly nicely with it.

To be honest I am pretty disappointed that something that is marketed as a beginner aircraft could be so problematic. My next will be one of the FT Quickbuilds made from foam I can buy locally.

Cheers

Lincoln
 

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#2
After the repairs and mods I decided to take her out for another attempt at flying last night. It was a bit too windy really but against my better judgement I decided to try anyway.

Getting rid of the major down thrust seems to have helped, the plane no longer seems to want to bank right and dive into the ground, but I have certainly not sorted out all the problems. She will now gently bank left but ailerons don't seem to overcome that tendency. I'm wondering if that is torque induced roll? Should I add that 3 degrees right thrust?

Anyway, as I said, it was too windy really so after about three attempts at getting airborne I decided to call it a night before I did any serious damage. Unfortunately the weather forecast for the foreseeable future is for continued winds of 20-30kph so I don't think I'll be trying again any time soon.

Cheers

Lincoln
 

rcspaceflight

creator of virtual planes
#3
Keep at it and wait for better weather. It can actually be a lot of fun flying in the wind, but you have to have the right craft and to know what you're doing. Flying in the wind isn't the relaxing fun that flying can be, but the trying to hold on for dear life kind of fun.

If you're willing to do all of those mods, maybe scratch building should be what you do next. The key is finding the right materials. Which is whatever is cheapest and can be used to build something that will fly. (I don't know what that would be in Australia. But I think there are a few threads on what is available in your area. Use what others are using. But I think it's some sort of Depron.)
 
#4
Thanks. I'm not ready to give up on it yet but I am quite prepared to ditch it if it becomes clear that it is a complete lemon. Pretty disappointed that Hobby King would sell such a lemon as a beginner aircraft though. In the end I can reuse everything except the foam in a scratch build so not a complete loss.

I have been involved in the foam board search in Australia and I am following developments in that with interest. I doubt I'll do anything with that until next year though, too much else on my plate at present including wanting to get the rest of the mainline laid on my garden railway. :)

Time to hurry up and wait for calm days. Probably early morning one Saturday is going to be my best bet for getting a flight in.

Cheers

Lincoln
 

rcspaceflight

creator of virtual planes
#7
I could be wrong, but around sunset always seems to be the calmest part of the day. The wind seems to die down and the light is usually perfect. Nothing worse than getting the sun in your eyes and crashing. The bad part is wanting to continue to fly even though there isn't enough light left. Too many people keep going and crash because they can no longer see.
 
#8
Around here (South-East Melbourne) the calmest part of the day tends to be at the start of the day although you are correct that the wind does also tend to drop off toward sunset too. Either way, I'll be waiting for some calm weather before I have my next go at getting this thing to fly right.

Lincoln
 

con244

Senior Member
#9
Hi Lincoln,
I hadn't seen that article before so thanks for that link. When I need foam board I usually only need a couple of sheets so I head to my nearest Art Supply shop. They have plenty in stock and although it's price (around $10 per sheet) its a larger sheet than the stuff they use on FT. It seems the only way to cut the price in Australia is to buy it bulk and unless you can get it local to you it may just be as cost effective to buy it from the US.
Con
 
#10
Con,

I think I'll get some from Cavalier in Geelong. Their price is pretty good and they deliver for pretty reasonable rates to Metro Melbourne areas.

Tonight the wind dropped off and the rain had stopped earlier so i took the opportunity to have another go. I added a little right thrust and went out. Wind was around 10kph which this plane should handle ok once I know what I am doing. I got in a few attempts at flight and the major problems appear to now be solved, no more unwanted rolls apart from pilot error. :D

I didn't manage to get her up high enough to work on trimming her properly because the wind was pushing me around a bit too much, I don't think it would have been a problem if I was more experienced. In the end I hit the ground nose first and broke the motor mount off the foam so it was time to call it a night. I am now more confident that I can get this thing to fly. I will undertake repairs and look for a still morning to try again.

Cheers

Lincoln
 
#11
Ok so I did my repairs last night and what do you know but this morning was pretty calm first thing. I had to go to work early (I work at a school) so I went earlier than I had to and got in a few launches out on the oval before work. Things went quite well this morning. The only thing I broke was the prop saver o-ring on the last crash. Control is still a little unpredictable but I haven't put my finger on why. Still, every time I fly it gets better. Soon I might even manage to get in a flight that doesn't end in a crash. :D

Lincoln
 

rcspaceflight

creator of virtual planes
#12
Ok so I did my repairs last night and what do you know but this morning was pretty calm first thing. I had to go to work early (I work at a school) so I went earlier than I had to and got in a few launches out on the oval before work. Things went quite well this morning. The only thing I broke was the prop saver o-ring on the last crash. Control is still a little unpredictable but I haven't put my finger on why. Still, every time I fly it gets better. Soon I might even manage to get in a flight that doesn't end in a crash. :D

Lincoln
You'll get there. It's an amazing feeling the first time you land your plane within 10 feet of you.
 

xuzme720

Dedicated foam bender
Mentor
#13
Try moving the battery slightly forward if possible. It sounds like you might have a slight tail heavy plane if it's squirrely and unpredictable...
 
#14
Good thought. I was flying with a 1000mAh this morning rather than a 1300mAh. The extra little bit of weight in the 1300mAh might just make the difference. I originally balanced the plane with the 1300mAh battery to be slightly nose heavy at the recommend 65-70mm cog.

I will get there.

Lincoln
 
#15
OK so I figured it out. Unfortunately the moment I figured it out was also the moment I crashed the plane and broke the motor mount off again and broke my first prop. Remember I am a newbie, I have about 10 crashes to my name now, but here is the reason I was finding it unpredictable...

I should have had both the rudder and aileron channels reversed! :black_eyed:

Part of the reason I was finding it unpredictable was that I had been using my SIM with the aircraft set up correctly and had built a certain amount of muscle memory. I have become reasonably proficient in the SIM, able to land, do loops and rolls, fly inverted and knife edge, all from the perspective of an RC pilot standing on the ground. So when I was flying my actual plane the actions I was making were doing the opposite of what I was expecting, but I hadn't quite made that connection until this morning in still airs again when I made what I KNEW to be the right corrective action and the plane did the opposite and crashed!

So when doing my pre-flight checks I pushed the ailerons and rudder and they both went the opposite way to what they should, I was fooled by the fact that in combination they were both reversed. :rolleyes:

I need to make some more repairs and now that everything is set up correctly I had reasonable confidence that I can make a better go of things.

Lincoln
(off to get shares in hot glue)
 

rcspaceflight

creator of virtual planes
#16
I use the High Five method that Flite Test has an episode about. You should always check the control surfaces before every flight. Not only direction, but also that they are working and aren't damaged.
 
#17
AH yes, high five. That could have saved me some grief. I went out today and bought myself a decent hot glue gun and some extra glue sticks. Makes repairing my foamie much quicker and easier.

Everything repaired now and while I was at it I checked and adjusted all my control surfaces and rechecked and adjusted my COG.

Taking my daughter out for a driving lesson now and if the wind is calm enough I might combine her driving lesson with a flying lesson for me. :)

As usual I will report back.

Cheers

Lincoln
 
#18
OK so no flying last night as it was too windy but...

I FLEW!!! This morning at sunup there was no wind so I was out there.

Firstly I got up nice and high, then trimmed her out and made a few turns, both left and right. Now I was starting to relax. Next I decided to check out the glide slope so I cut the throttle. She put her nose down a bit a lost altitude quite quickly. Is this a sign of being nose heavy?

Anyway I carried on flying around for a few minutes nice and high up. Having the height was good a couple of times as I made errors and was able to correct. Everything was going so well and then she seemed to become quite unpredictable for some reason. As I strained to see what was happening with her I realised that the battery had fallen out and was hanging below the plane by its cable. Glad I have the XT60 connectors and not the wimpy ones that were standard on the ESC. I was able to get her under control and gently bring her down for a soft landing in the grass about 30 metres away. No damage.

I figured it was about time to change the battery anyway so I popped another in, made sure it was secured better this time, and went up again. A first for me, getting onto a second battery in the one outing. ;)

After a few more minutes of flying around I made an error a little too close to the ground. This resulted in an unintended nose first landing. ;) The only damage was bent landing gear (no biggie) and a lost prop shaft adaptor when the prop came off the prop saver. Note to self, glue the shaft adaptor into the prop.

So all up a very successful and enjoyable time with a couple of lessons learnt. And no repairs to do this time. :D

Cheers

Lincoln
 
#19
Glide slope for a given plane is really more of a personal preference sort of thing. This is where that elevator trim button on the side of stick gimbal comes into play. Case and point, although somewhat of loner I do occasionally fly with others and when given chance fly their planes. Its sort of a joke cause what's trimmed "perfect" for my friend doesn't work for me and I ultimately hand his plane and radio back "all out of wack" by his standards. Throttle cut and off the sticks the plane should not want to pull up and go into a nose high attitude, best way to wreck a good model. Anything aside from that (with the exception of full on nose dive) is preference....yes CG does effect this but with the type of trainer you are flying my guess is even if you are close to CG, maybe off a tad all else can be tweaked via some up or down elevator trim. There is a saying many of us know that is repeated often ( and no Josh Bixler did not coin the phase) " a nose heavy plane may fly poorly but a tail heavy plane only flys once"
 
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#20
One more tad bit of advise....until you get a bit more comfortable I would suggest you land the plane to trim in SMALL increments, repeat this process until satisfied. Just a quick toss up, test trim, circle around, land and adjust. As a new flyer your hands can get pretty full trying to trim while maintaining level flight, have seen more than one new flyer get too aggressive with trim tabs whilst in air, panic and plow into the ground at full throttle.....absolute carnage.