Bench Testing Your Heli

[dze]

first i wouldnt do this with a large heli, but 250/450 size i do it in my living room on the floor in front of a window preferrably when the sun is shining in so i can see it good, and put tools i need to the side .. i lay down on the floor and hold the skids with my hand and spool it up with the tx off to the side with the other hand .. tracking should be dead on at zero pitch, center stick, at the headspeed you plan on using .. a large metal tool like a pipe wrench through the skids is probably a safer alternative to using your hand and a couple of pounds will hold anything 450 or smaller just fine ..
..
..once i have center stick zero pitch tracking set, i change out the lipo, and check it again but flip to idle up and see how it looks with a little pitch bite in both directions and tweak it if necessary to get a good happy medium if the blades arnt so great .. also while im there i note the stick position on the collective hash marks on the tx and see if i get approximately the same pitch bite at equal distances from center stick pos and neg .. this tells me if i really have my zero in the right spot on my stick ..
..
.. other notes ... this is just how i do it on smaller helis and i wouldnt call it safe .. also im not worried about it so i dont need to be preached to lol. DO NOT get careless and hit the cyclic while your testing thats a big no no - a hand can hold pitch just fine on the skids but cyclic can tip it and it could get away from you and then your going to be rebuilding it again .. use a fresh lipo not an old test lipo to set tracking .. all it takes is a quick look i wouldnt sit there and stare at the blades for any amount of time it just increases risk to your face and eyes ..

[rdlohr]

If you are careful setting up your head with a pitch gauge, you should only ever have to adjust a top link 1 turn or at most two. Just hover it outside at a safe distance and its easy to see when its right. Turn 1 turn on one blade remembering which blade and which direction you went. If it tracks you are done. If it get worse, you turn two turns the opposite direction. Repeat if necessary. Definitely good advice to not tie down a heli or spin it up in the house.

Rick

[Larry227]

Originally Posted by e92vancouver

I like this. You fold the blades out to the left or the right of the heli?

Yes. Like this

[banditpowdercoat]

My 400 and 500 I hold them in my hand, 0 pitch finger on TH. My arms are long so not an issue. but over a 425mm blade i won't

[npomeroy]

With a 450, I place a narrow plank through the skids, on a grass lawn, hold the plank down with 2 bricks or similar, and lie on the ground about 5 metres away to check the tracking. I think ideally you need a bit of positive pitch to make it realistic, but something below hover throttle.

[Commodore8888]

Setting up your head with a pitch gauge (especially the digital ones) will often get you dead on or very close (I know I get it) to .5 or less variance between the blades for tracking. And even then, if they go out of track you can pop it on and check to see which one's high or low.

Barring a pitch gauge I check my pitch in the air. Bench testing I do is done without main blades on. If you really wanted to do a blades on test, put plexiglass between you and the bird (or a wall) and bolt the skids to something. Pull on the head to make sure the skids aren't going to go easily if at all. And if you can do it somewhere without a ceiling. I don't trust any mechanical part enough to hold it with my hand unless it's something like an mcpx with little inertia. I am guilty of "partially" spooling my 450 while holding it to see how something is moving on it like binding. It never gets above 400 or so rpm. Probably less.

[rdlohr]

Originally Posted by npomeroy

With a 450, I place a narrow plank through the skids, on a grass lawn, hold the plank down with 2 bricks or similar, and lie on the ground about 5 metres away to check the tracking. I think ideally you need a bit of positive pitch to make it realistic, but something below hover throttle.

Now think about that for a second. Four tiny screws into plastic hold the skids on. Not really a good idea.
Even when the screws hold, it can stress the heli in ways it was never designed to handle.
Rick

[rdlohr]

Originally Posted by banditpowdercoat

My 400 and 500 I hold them in my hand, 0 pitch finger on TH. My arms are long so not an issue. but over a 425mm blade i won't

So you spin it up at arms length from your head. Again, probably not the best idea.
Rick

[mkovalcson]

I built this test rig which I have used with my T550E and Protos 500. It should handle a 700 sized heli as well.
The 2x4's at the bottom have a bit of weight and I stake it into the ground until it is level and also securing it.

There is a ball level in the middle of the lazy susan swivel, so the heli can spin, and heli is lifting two pieces of 1/4" oak plywood, a lazy susan swivel and 4 fairly light PVC pipes. It cost me less to build than 1 set of 550mm blades and has paid for itself.

Click here to see it work. http://www.onecrmpro.com/temp/HeliTest2.mp4

[rcflier1]

me thinks we make too much of this. even if the tracking is off, it's not going to crash.when you lift off the 1st time, you see whats up. land and make a turn or 2 till it's right.

[rdlohr]

Exactly. All these ways of holding the heli down, although some are very cool, are putting you in a situation where you are taking completely unnecessary risks.

Rick

[mkovalcson]

Originally Posted by rcflier1

me thinks we make too much of this. even if the tracking is off, it's not going to crash.when you lift off the 1st time, you see whats up. land and make a turn or 2 till it's right.

In the days of flybars, I would say that is true.

However, my first time setting up my electronic flybar I had a servo mapped backwards.

Interestingly enough I heard from a LOT of people very experienced heli people who had similar misadventures on their first flight.

OK, my bad I fixed the problem, but guess what? It crashed on takeoff again!

It turns out the my main bearings were shot from the first crash and I hadn't realized that and they were confusing the electronic flybar so it just rolled into the ground.

At this point I'm out 2 sets of main blades, tail blades, boom, TT, bearings and a LOT of time!!!!

So I built this test rig and sure enough reproduced my failure and sent the flight log to Skookum where they told me it looks like my main bearing was possibly shot.

So it saved me another crash! I fixed the issue tested again all was fine and I flew.

[npomeroy]

Originally Posted by rdlohr

Now think about that for a second. Four tiny screws into plastic hold the skids on. Not really a good idea.
Even when the screws hold, it can stress the heli in ways it was never designed to handle.
Rick

OK point taken. I did think about this and had the skids zip-tied to the frame as a back up. I should have said.

[mkovalcson]

Originally Posted by npomeroy

OK point taken. I did think about this and had the skids zip-tied to the frame as a back up. I should have said.

With the helis I've tested with their landing gear was plenty strong enough, and it saved the heli from a lot of damage with a blade strike!

Both the T550 and Protos 500 have the landing gear very stoutly screwed to the frame and the skids slide through the landing gear such that they are not going to come out.

What heli are you looking to try this with?

[banditpowdercoat]

Originally Posted by rdlohr

So you spin it up at arms length from your head. Again, probably not the best idea.
Rick

Not everything has to be the best, safest idea. If that were the case, we all beter live in kevlar bubbles and never leave our houses.


Sent from my iPhone using Tapatalk

[npomeroy]

Originally Posted by banditpowdercoat

Not everything has to be the best, safest idea. If that were the case, we all beter live in kevlar bubbles and never leave our houses.

Yes but Bandit... there are big risks and smaller risks. Holding spooled up heli in your (long) arms? You SHOULD get inside a kevlar bubble for that trick!

But more generally:
There is an issue for newbies setting things up correctly with the tradeoff between precision and safety. I was simply not confident/competent to hover my first CP heli in a way that I could usefully focus on the tracking. That's why I did it on the ground (safely away from me). ALSO the newbie is more likely to be inexpert at setting pitch with a gauge and NEED to confirm the tracking spun up.

My spinning up, held down on the lawn 5m away at worst could result in the heli ripping out the screws but I actually think that is unlikely at hover power (you can after all hold and shake a heli upside down by the skids - similar forces). And if it did break loose I'm not likely to be hit by it (or not any more than any number of other control mishaps).

I'm always somewhat wary when my flying heli has its blade disk at eye level anyway.

I think the biggie is FBL controllers going crazy with a tethered heli. I'd like to know if this has actually happened.

Nelson NZ

[rdlohr]

Originally Posted by banditpowdercoat

Not everything has to be the best, safest idea. If that were the case, we all beter live in kevlar bubbles and never leave our houses.


Sent from my iPhone using Tapatalk

Just trying to help you and everybody who reads this. We all pick which risks are worth taking.
If even one person is saved an injury from this thread, it was well worth taking the time to post.
Rick

[Bob O]

Originally Posted by rdlohr

SNIP although some are very cool, are putting you in a situation where you are taking completely unnecessary risks.

Rick

+1

Unnecessary being the key word.

A lot of accidents and injuries are preventable. The best way to prevent an accident and/or avoid an injury is to avoid the situation that's likely to result in one.

[DominicD]

Originally Posted by banditpowdercoat

Not everything has to be the best, safest idea. If that were the case, we all beter live in kevlar bubbles and never leave our houses.


Sent from my iPhone using Tapatalk

Sure, but it's also a bad idea to knowingly put yourself into dangerous situations for no gain.

Originally Posted by e92vancouver

When you are bench testing your heli (ie. blade tracking, etc.), what method do you use to secure it to the table?

I was thinking some old blades over the the landing gear skids secured to the table with duct tape.

I would on the kitchen table so I can't screw anything into it (Live in a condo so no work bench)

Bench testing a heli is both pointless and dangerous, the danger increasing with the size of the heli. Tracking HAS to be done with the heli in the air. Without the weight of the heli hanging from the blades the blades are NOT loaded properly and will not track as they do in flight. Personally I'll use the blade folding trick in a pinch and if i want precision I'll use one of Rick's tools that you can buy at readyheli. I've been in this hobby for years, built an uncountable number of helis and can say that after reading this thread people put WAYYYY too much thought into tracking. I haven't had to adjust a blade for tracking in a few years now, every time I check my tracking is bang on. Heck even eyeballing it you should never be more than a turn of a link off. There is no need for lasers, bench testing or anything that takes more than a few seconds. The hardest part of tracking should be seeing the blades.

[npomeroy]

Originally Posted by DominicD

... Tracking HAS to be done with the heli in the air. Without the weight of the heli hanging from the blades the blades are NOT loaded properly and will not track as they do in flight...
.

A tethered heli at hover power-pitch will load the blades.