Go Back  RCU Forums > RC Airplanes > Kit Building
Reload this Page >

Giant Astro Hog Laser Cut Kit - Jerry Bates

Notices
Kit Building If you're building a kit and have questions or want to discuss kit building post it here.

Giant Astro Hog Laser Cut Kit - Jerry Bates

Old 02-04-2021, 11:51 PM
  #151  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

I connected the aileron servos using a 4-40 threaded rod. Also I do think that on such a short connection it is sufficient and will not bend under load (the actual diameter of the core of a fully threaded 4-40 rod is smaller than the diameter of a 4-40 rod), I decided to sleeve it.
I then connected the receiver confirming that all is working as expected.

I decided that I did not like the look of the small tailwheel, so it was replaced with a 1 3/4" diameter wheel I had lying around.





Cheers,
Eran
Old 02-05-2021, 06:41 AM
  #152  
speedracerntrixie
My Feedback: (29)
 
speedracerntrixie's Avatar
 
Join Date: Jun 2010
Location: Happy Valley, Oregon
Posts: 8,111
Received 66 Likes on 63 Posts
Default

A couple words of caution. Your aileron linkage may be prone to flutter. I would suggest making your control horn longer and replacing the plastic servo arm with an aluminum arm. Running a ball link on a plastic arm can cause the plastic arm to flex and the short control horn gives the mechanical advantage to the control surface not the servo. A split second at the right harmonic and you could be left flying without ailerons.
Old 02-05-2021, 03:38 PM
  #153  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

Thank you speedracerntrixie, I will look into it again.
I am very rarely using ball link connection on my aeroplanes, and used it in this case due to the odd geometry (aileron horn and servo not on the same plane).

Cheers,
Eran
Old 02-05-2021, 11:53 PM
  #154  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

Looking at the aileron control rods yesterday, I was not 100% happy with the convoluted setup (ball link, threaded rod, sleeve) I ended up with. Then, this morning as seen above, came the commented that it may be prone to flutter (which I am not sure that I fully agree with).
I decided to replace it with my "usual" simple setup of 4-40 rod and EZ connector at the servo side. When I looked into it originally, I didn't think it would work in this specific case, however, I am pleasantly surprised that it is working well. The articulated joint at the aileron control horn is well designed and resolves the "misalignment" of plains (servo to control horn).

Since there is not much else I can do on this project until I receive the cowl (which Manni kindly sent to me) except for small jobs here and there, I experimented with painting the headrest in leather colour. Not going to win any awards, but will do.



Cheers,
Eran
Old 02-06-2021, 06:51 AM
  #155  
speedracerntrixie
My Feedback: (29)
 
speedracerntrixie's Avatar
 
Join Date: Jun 2010
Location: Happy Valley, Oregon
Posts: 8,111
Received 66 Likes on 63 Posts
Default

Earn, please regard my comments as someone who wants you to enjoy this airplane for many years. The last thing I want you to do is feel that I am picking on your work. On the subject of you aileron linkage, while you did make an improvement, I still have concerns. Eliminating the ball link does eliminate the possibility of the servo arm twisting however you reduced the control horn length even more. From the pictures I would have to approximate your aileron thickness around 5/8" to maybe 3/4". Let's go with best case and say 3/4". So from hinge center to outside surface of the aileron is 3/8". The height of the pivot hole on you control horn looks to be maybe 3/4" above the aileron surface. That gives a moment arm of 1 1/8". The servo arm from center to the hole you have chosen looks to be 1". This is close to a 1:1 ratio which will result in close to 3D control surface throws. Of course you will need to reduce the throw via your TX which will greatly reduce your resolution. Keeping this setup will also work your servos harder and consume more battery power. Best case scenario you order up some aluminum servo arms and go back to the ball links and replace the screw being used for your control horn with a longer one then use a hole in the servo arm closer to center. The object is to get the desired surface movement without having to electronically reduce servo travel. That said, you could also flip your push rod so it inserts into the arm from the top which would allow you to unscrew the flag a bit in order to lengthen you right control horn. Obviously I would rather you go with the first option. Reason being is that as the aileron moves because of the aft location of your control horn the angle ( height ) in which the push rod meets the servo is going to change.

Last edited by speedracerntrixie; 02-06-2021 at 06:55 AM.
Old 02-06-2021, 04:48 PM
  #156  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

speedracerntrixie - Thank you for your concern also we may need to agree to disagree in this case.
The recommended travel for the ailerons as detailed on the plans is 1" up and down which is what currently set at 100% servo travel. I will leave it at this setup for the test flight and may adjust it once I had a feel for the control. The servos are way over-spec for this aeroplane ailerons requirements and they will deal with any geometry deficiencies forces with ease.
A fact that is not obvious (if the build was not followed closely) is that the pivot line for the aileron is further back from the wing TE (at the aileron) then it seems (pivoting on a rod and not using conventional hinges). It is directly under the control horn articulating point.

I have not too dissimilar setup on a larger 3D capable aerobatic aeroplane (also 3D flying is not my style) for many years now and it yet to fail me, so I am reasonably confident that it will work just fine for many years on this aeroplane as well. I have seen much inferior setups lasting years on aeroplanes flying much more demanding routines without fail. Please do not take the above as me disregarding decent mechanical setup.

Cheers,
Eran
Old 02-06-2021, 05:28 PM
  #157  
speedracerntrixie
My Feedback: (29)
 
speedracerntrixie's Avatar
 
Join Date: Jun 2010
Location: Happy Valley, Oregon
Posts: 8,111
Received 66 Likes on 63 Posts
Default

No worries, I understand that my suggestions were unsolicited, we can agree to disagree.
Old 02-08-2021, 03:46 AM
  #158  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

I installed the engine, routed the ignition cables and mounted the ignition module,








Cheers,
Eran
Old 02-09-2021, 10:09 PM
  #159  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

With an attempt to bring maximum weight forward anticipating a tail heavy aeroplane, I mounted the 6 cell NiMh ignition battery as far forward as I could, not far behind the firewall. It had to be mounted in a way which allows the battery to be taken out (as access is required to the Nylon insert lock nuts securing the engine mounting screws).
I mounted the main landing gear to the wing using brackets made by a friend.
Last, I mounted the ignition LED light to the side of the fuselage.









Cheers,
Eran
Old 02-11-2021, 01:37 AM
  #160  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

It was not my finest day in the Cave, as I was properly struggling with fitting the fuel tank. I started with installing a fuel dot to the side of the fuselage as it will not be accessible once the fuel tank is in position.
What I ended up constructing is a tray that is screwed into hardwood mounting blocks at the back and is held into a slot at the front.
I had to cut the servo tray to allow the fuel tank clearance to slide into position.










Cheers,
Eran
Old 02-11-2021, 10:28 AM
  #161  
sensei
 
sensei's Avatar
 
Join Date: Jul 2002
Location: SAN ANTONIO, TX
Posts: 2,760
Received 10 Likes on 9 Posts
Default

Getting close now!

Bob
Old 02-11-2021, 11:25 PM
  #162  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

Bob - Yes, it is getting very close. Unfortunately the cowl is still waiting with DHL in Germany (since 7th January), so it is not likely to be here on time for the test flights.

I was setting the controls for the elevator, rudder (pull-pull) and throttle today







Cheers,
Eran
Old 02-12-2021, 06:40 AM
  #163  
Nece
 
Nece's Avatar
 
Join Date: May 2018
Location: Munich/Germany
Posts: 21
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by erans View Post
... the cowl is still waiting with DHL in Germany (since 7th January), ...
Eran, the package left Germany on January 9th and is on its way to Australia. Probably by ship, I hope it's not a rowboat ...
According to DHL, the delivery time should be around 25 working days.

How you build the RC system is exemplary. If I see it that way, I have to improve my Astro Hog a little ...

Manni
Old 02-12-2021, 03:49 PM
  #164  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

Hi Manni
Thank you for the clarification regarding the shipping (by the way, all the boats destine to Australia must be rowboats ; ) ). The tracking page is in German and I thought it is still in Frankfurt.
Also, thank you for the nice comment. I am getting ready to put the aeroplane together and figure out where I am in regards to the CG, as I am still worried it is tail heavy (and I am running out of good options to distribute weight without adding any).

Cheers,
Eran
Old 02-13-2021, 01:07 AM
  #165  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

I made a retention tab for the fuel tank vent, then connected the fuel line and ignition sensor lead to the engine.
I also connected the ignition spark plug and earth leads.






Cheers,
Eran
Old 02-15-2021, 12:57 AM
  #166  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

Slowly ticking off the small item list.
The muffler is on, which required me to relocate the fuel tank vent and make a small bracket for it.
I made a removable tray for the PowerSafe receiver (over the cut-out I had to do to insert the fuel tank). I Then mounted the receiver, routed the wiring away from the throttle servo and installed the three satellites in three orientations.
Last, I installed the optical kill switch and its LED.






Cheers,
Eran
Old 02-19-2021, 01:26 AM
  #167  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

After installing the switches a couple of days ago, today it was time to check the current CG situation. As expected, the aeroplane is tail heavy, requiring roughly 240g near the firewall for balance.
Hopefully with the cowl and spinner it won't be too far off correct balance.
I took the opportunity of the aeroplane being assembled and placed it on "its legs" for the first time (it looks better in reality than in the attached over exposed photos). There is plenty of prop clearance which is always good news.

Last, I decided to relocate the receiver and place the batteries tray in the now vacant space.









Cheers,
Eran
Old 02-22-2021, 12:17 AM
  #168  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

I made a removable battery tray.
This was the last item to do until I receive the cowl. Therefore there will be no further update until then.





Cheers,
Eran
Old 02-23-2021, 05:48 AM
  #169  
sensei
 
sensei's Avatar
 
Join Date: Jul 2002
Location: SAN ANTONIO, TX
Posts: 2,760
Received 10 Likes on 9 Posts
Default

Boy it really turned out great looking, well done! I sure hope your cowling comes in soon...

Bob
Old 02-23-2021, 03:35 PM
  #170  
erans
Thread Starter
 
Join Date: Jun 2008
Location: Perth WA, AUSTRALIA
Posts: 930
Likes: 0
Received 4 Likes on 4 Posts
Default

Thank you Bob.
I am looking forward for the cowl to arrive, however, at these times where mail is slow worldwide it is a game of patience.
I put the Astro Hog away, tidied up my Cave and started another small scratch build project, a Don Anderson Big Stik 60 (Outerzone free plan oz11467),

Cheers,
Eran

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.