General Pitch help

[Tony]

When you are at mid stick, write down the number. You said +6 above. Now, go full positive pitch, and write that number down. then full negative and do the same. You should have the same number of degrees from +6 in both directions. If you do, or you are close, then yes, you will adjust the long links, But, if you have more positive than negative, then your swash is too high and you need to shorten your servo links. And vice versa.

 

[corsair_pilot]

finished doing this to mine today. I think it's ready to go up, but after all the fiddling I don't want to get it up and crash it haha
Good luck Treff, hope you get it up and going

 

[Tony]

Here are 4 pictures of the 4 sides of my head on the HK450GT. Only difference is going to be I have nothing but adjustable links, whereas you only have two. Same principal though.

 

[treff]

Hi all. Another problem. I have adjusted all head pushrods to the Align drawing but now my pitch measurements are as follows midstick with IU set. 7 degrees posotive. Full throttle 30 plus degrees posotive and minus 4 degrees negative at low throttle. Which means that the swash is to high. Unfortunately I have run out of adjustment on the swash push rods they are as short as they will go. Or is it that I should adjust the three swash pushrods longer. I'm getting confused. Any Ideas are most welcome.

 

[Tony]

Longer will give you more positive and less negative. With your Tx at mid stick, verify that you are at 50% pitch on your curves and post a picture of your head and servos. Lets see if we can figure this out.

 

[Westy]

you have 37º total pitch range (movement from bottom stick to top stick) which is nearly 100% more than you need (if you were using +10 and -10º) reduce you Swash menu PIT setting so you get down to about 20º total pitch range and see if you can tweak it from there.

 

[treff]

Hi all and thanks again for all the replies. I have attached a picture of the head set up. Throttle set to 50% and IU selected. At midstick pitch is 5 degrees. Full throttle 35 plus and at zero throttle minus 7 degrees. Hope the picture helps. The swash mix is set to +60 for each. Thanks.

 

[Tony]

Looking at your long links and the mixing arms, you need to shorten those links. The mixing arms should be even with each other as I posted in my picture. Okay, so my heli is not perfectly level, but it's close lol.

Shorten those links until you get the mixing arms level then recheck your pitch. Be sure to post up the results. Pictures help as well hehe.

 

[Westy]

try reducing your swash pitch to 35 and see how much that reduced the total pitch range...... then see if you get 0 at mid stick

 

[treff]

Thanks both for the suggestions which I have tried but it makes no difference to get to zero pitch. The big problem is there is so much play in the fly bar cage that is it impossible to set up. Level the gauge on the fly bar and I have almost an inch of play up and down. I sure that is not right. I can no longer shorten any of the arms, they will not adjust anymore. I have tried altering the pitch to 35 in the swash settings and I still can not get equal amounts from the centre of the throttle. I can not believe the Align drawings would have the wrong dimensions for the pushrods. I know they are approximate but the swash is almost banging on the mainshaft collar so I think something else is not right. I am beginning to think I have installed the oneway bearing the wrong way or something silly. I will break it all down again and start from scratch to see if I have made some stupid error. Thanks for all the help.

 

[Westy]

when you reduced your swash pitch setting .... how much total travel did you have in degrees?

eg
top 15
bottom - 5

- - - Updated - - -

can you take a video to show us?

 

[treff]

Westy. I've only gone and bloody cracked it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I'm gonna enter this in the Guiness book of records. "the longest ever adjustment of the helicopter pitch in the world" I now have 10 degrees up and down and the magic zero pitch at midstick. No need to applaude gentlemen but I would like to thank a few people. First my Mother, teachers and all the friends I've made here. With out all the great input I would still be twiddling with me ball nose pliers. And please do not ask me what I did to correct the fault because I do not know. Maybe I took me glasses off and looked from a different angle, I honestly do not know. I adjusted both blades to get zero pitch with the long push rods and like magic it all fell into place. Yesterday, no matter what I did I could not get equal movement. So, again thanks all round to the very friendly and knowledgable guys on this site. Brilliant.

 

[corsair_pilot]

Great news Treff!!
Now to get the beast off the ground and into a hover!!
Good luck man!! It's all starting to sound good!

 

[Tony]

I think I mentioned way back when to shorten those rods a LOT to get it where you need it. Either way, you have it done now, so grab yoru camera and fly it!

 

[Lee]

I think I mentioned way back when to shorten those rods a LOT to get it where you need it. Either way, you have it done now, so grab yoru camera and fly it!

Yep me too

 

[Westy]

so where is the maiden footage! haha

 

[treff]

Again many thanks to all for the help. Heli is now waiting for the weather which wouldn't you know as turn for the worst. Wind, rain, just have to be patient. I did run it up for the first time yesterday and it sounds great. I almost lifted off when a gust of wind go under the blades. Video will follow soon as the weather improves or I can find somewhere indoors.