Hangar 9 PT-19 Technical Notes

[PeteBergstrom]

Hangar 9 PT-19 Technical Bulletin

Pushrod

It has come to my attention through numerous reports from my friends on these forums and subsequent personal inspection of current stock on hand that some, if not the majority, of the modified Z-bend in the bellcrank portion of the pushrod is bent opposite to what we intended and to what we had shown in our instruction manual. I apologize for this error.

Using the included pushrod is virtually impossible in the inner hole of the bellcrank because of interference issues with the bellcrank mount itself.  Many have inserted the pushrod into the outer hole on the bellcrank because it ‘works and fits’ there.  Unfortunately, this will result in entirely too much control throw and make the airplane very sensitive, even when you use the outer hole of the elevator horn.  The design is for the inside hole on the bellcrank and the outer hole of the control horn … this coupled with the proper specified balance point provides control response that is balanced, predictable and very comfortable.

Action Item

1.   If you do have a pushrod end that is bent opposite to what is shown in the instruction manual, please discard this part.  We will have replacement parts bent in the correct direction in about 10 days here.  The faster alternative is for you to bend a replacement part out of 3/32 music wire. (Or, if you have a Dubro 4-40 pushrod, that material is the right size and the strength is very adequate to the task)  Please see the attached picture.

 

2.   Insert the replacement pushrod in place of the original and continue with the installation instructions.
3.   Please make sure you use the inner hole on the bellcrank, and the outer hole on the elevator horn.


Control Line Length

We have inspected many of the sets of control lines we have in-stock, and we have found varying lengths; anywhere from 60’ (as specified) to 68’.  Upon investigation with the factory we discovered they using an imprecise method of measuring lines.  This is what caused the varying lengths.

Action items

Please take the time to measure the length of your control lines.  If the lines you have are over 62’ in length, you may have line tension problems with the airplane as it approaches the 45 degree point of the circle, and will certainly have difficulties completing any overhead maneuvers.  Take the time to cut your lines to the specified 60’ length before flying.

We are also waiting on accurately cut lines.  If you prefer to send yours in for a replacement these should be available by April 1st.


Once I again, I thank you all for your support and patience with this.  Rest assured that Hangar 9 is most interested in your total enjoyment of our products and your hobby, and we continue to work hard toward that end.

Yours,

Pete

[Mark Scarborough]

Pete, Kudos to you for making this info available with fixes.
Your efforts into our hobby~sport are a great asset

[PeteBergstrom]

Thanks!  Only wish I didn't have to make the fix in the first place

[john e. holliday]

Maybe that explains the first loops of Dan McEntee's PT-19 I watched him fly for the first time at the Ice-O-Lated contest.  Looked at the plane up close and liked what I saw.  Don't know if he ran the engine prior to first flight or not.  We left as soon as he landed.  Looks like a very well thought out design.  DOC Holliday

[Dan McEntee]

 Yeah, the first two flights were, uh, interesting! I've since done a rework of the controls but the weather hasn't cooperated for more test flying.
  The bell crank is like the kind that used to come with TopFlite kits, that had an off set output arm, or more like two popcicle sticks laid one on top of the other at 90 degrees to each other. My push rod was bent backwards, and even after I re-bent it the correct way and got it installed correctly, it was interfered with by the bell crank mount because the out put arm was off set in that direction. I think that the bell crank is installed upside down and there isn't anything you can do about that. I solved the problem by using a short section of 4-40 push rod and 4-40 clevis with a fuel line retainer. I assembled the clevis to the threaded portion of the push rod and soldered it in place, then cut the rod to length to match the original section of wire. I had to make a small zigzag in the wire for proper alignment, and it is a bit tricky installing it in the bell crank, but it worked and movement is full and smooth. We'll find out soon how well it all works out.
   The engine run was anything but smooth, and when I checked things out at home, I found that there were several screws loose on the needle valve mount. These, I'm assuming, are for allowing you to mount the barb fittings in several different configurations for ease of fuel line installation. I haven't tested the engine yet either but hope to do that soon. With the temps as cold as it was that day, everybody was having some sort of engine run issue, so I'll attribute some of the trouble to that also.
   I do like the look of the airplane, and understand what market it is intended for and don't expect it to be a world beater or NATS final 5 contender. I'll use it for sport flying and demonstration purposes mainly, and if someone comes in to the hobby shop that I work part time at, I want to be able to make an honest recommendation about the airplane or any mods or changes that may need to be made or will work better.
   On a pure aesthetic note, I think that it's a bit too short coupled, and would look even better if the tail moment were just a bit longer, but that's just me
   I'll report back when I have made further test flights.
   Type at you later,
   Dan McEntee