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Giant Astro Hog Laser Cut Kit - Jerry Bates

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Giant Astro Hog Laser Cut Kit - Jerry Bates

Old 06-23-2020, 10:56 PM
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erans
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Default Giant Astro Hog Laser Cut Kit - Jerry Bates

I finally bought the Jerry Bates Giant Astro Hog Plans and Laser Cut Kit from Laser Cut Kits Australia.
I was looking into this project for a couple of years now. I first bought the plans (late February) to review the task ahead and then bought the short-kit (I think) in early May (and sat on it for a while...).

The plans are incredibly detailed, and I will rate them as some of the best I have ever seen. I knew what to expect as I saw JB's plans for the 1/5th scale Hawker Tempest before (purchased by a friend and they were also very good).
The one downside to purchasing JB plans is that it seems that none of the fibreglass accessories is available from him. He never answered my friend emails, and he never answered my own inquirers regarding the cowl and headrest for the Giant Astro Hog. Lucky that in this case I don't care and will probably won't bother with a cowl (as was the original Astro Hog) and will make my own headrest.
I will also make few changes to bring this old design to be used with modern radio equipment and current control setup.

I am still short of couple of items before I can actually start the build (I will be starting with the wing construction), however, I used my time to test forming 3/32" sheet piece to a LE stock by soaking it first in warm water (as I have no intention of using Ammonia as suggested on the plans). It seems to work fine.
This may be a slow pace build then some other I posted (but it should be much quicker then the Me-109 build), so apologies in advance ; )










Cheers,
Eran
Old 06-25-2020, 11:53 PM
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After removing the laser cut ribs for half a wing from the balsa sheets, I tested the wet formed 3/32" sheet on a rib and it fits perfectly.

Today I was plying with the idea to make the wing-tips of the Astro Hog removable. This will shorten the wingspan by 400mm (to 1,900mm). I know from past experience that around 2,100mm wingspan one-piece wing just fit in my Mazda 6 waggon without obscuring the driver view out of the passenger window.
I did consider building the wing as 3 piece (cut after the wheel mounts), however, this solution was a bit more involved and I am too lazy.
My plan is to use two "W4" plywood full length ribs, substituting the "W6" short rib (as it had the aileron behind it). This modification will shorten the aileron by 3mm (see photos).
Once the decision was made, it was time to create some dust in my Cave. Tracing, cutting and sanding two 3mm birch plywood and two 2mm Lite ply newly created "W4" ribs.








Cheers,
Eran
Old 06-29-2020, 02:24 AM
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I thought that I will be glueing some ribs today, but I realised that I am still missing some spruce.
What I end up doing was dry fitting the ribs and having a look at the stages I will need to do when I am ready to glue everything. The laser cut fit is good, which helped.
I then glued the main spars to the main spar doublers. I also cut a hole in the ribs for the servo leads (my servos will be placed next to the ailerons) and wet formed 1/16" balsa around a poly-pipe for the TE of the ribs adjacent to the ailerons.









Cheers,
Eran
Old 06-30-2020, 01:59 AM
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I built one several years ago. Unfortunately, a bad receiver got it and it was destroyed on the first flight. Too bad, as it flew fantastic. I scratch built a cowl and headrest out of fiberglass. I wouldn't call the control system antiquated. The aileron torque rods run all the way into the center of the wing to keep the servos and linkage hidden. They are also counter balanced. It results in a very neat, clean look. If I were to change anything about the control system, it would be to put the aileron servos in the wing center section instead of the fuse. I didn't like having to attach the aileron pushrods to the torque rod ends through the cockpit.

carl
Old 06-30-2020, 04:10 AM
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Carl - Thank you for the information regarding your Giant Astro Hog. I was surprised that I could not find much information regarding this JB design considering the popularity and number of forum threads for his other designs .
While I do not mind that the controls will be exposed, I will give the ailerons torque rod design a second thought. I will definitely have the aileron servos in the wing, either within the centre section using the torque rods or next to the ailerons.
Considering the available torque of the intended servos, it is unlikely that I will bother with the ailerons counter balance.
Any chance that you have some photos of your Giant Astro Hog that you can post here?

On a positive note for my build, I sourced today the missing Spruce and I should be able to get going soon (once time permits).

Cheers,
Eran
Old 06-30-2020, 08:41 AM
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There is a pic of me with the astro hog on Jerry Bates' website.

carl
Old 06-30-2020, 03:24 PM
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Thank you Carl. I did see this photo on Jerry Bates' website.
This is one of only two photos I am aware of of this model. A very nice finish if I may say so.

Cheers,
Eran
Old 07-01-2020, 01:23 AM
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Thanks. The finish was uncertified aircraft fabric and Randolph dope. I was sick when I lost it. The only thing I salvaged from it was the head rest. I have never so completely destroyed a plane.


carl
Old 07-02-2020, 10:48 PM
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After test fitting the wing (actually half of the wing) few times, I finally glued it. It came out very nice.
In addition, I am still playing with ideas for securing the ailerons hinging. I am looking at birch plywood "bushings" for strengthening the passage through the ribs as well as possible retention of the carbon fibre rod to prevent side movement. I cut few pieces which you see in the photos, but this is still not finalised.
I also test fitted my "end rib", but am yet to commit to anything. Time for some more coffee while I am thinking about it all.













Cheers,
Eran
Old 07-14-2020, 03:25 AM
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I finally cleared the desk in my Cave of maintenance work on couple of aeroplanes and am back to the build.
I made couple of 1.75" blocks to support the right wing-tip when checking for correct dihedral.
I then glued the Spruce spars to the Spruce "spar doubler".






Cheers,
Eran
Old 07-15-2020, 10:40 PM
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I glued the secondary spruce spars to their corresponding spruce doublers (as was done with the main spar).
I then made the left wing panel and once the glue dried, I attempted to dry fit the wing.
Two things were immediately obvious in the process:
1. That the blocks I made for the wingtips to hold it in the correct dihedral will not do. I fabricated proper cradles from the laser cut "negative" of the ribs, which worked very well.
2. The dihedral brace has substantial wrong angle to it (I did check and the laser cut perfectly fit the plan).

As I already glued the dihedral brace to the right wing panel, I glued the wing with it as is and will fix this once it is dry.










Cheers,
Eran
Old 07-16-2020, 03:42 AM
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I just realised that I miss red the note regarding the support of the W6 rib for dihedral.
The height was for under the rib and not the rib tip as I was reading it. In that case, the brace is of correct angle. Too late for me tough...

Cheers,
Eran
Old 07-16-2020, 11:44 PM
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A short working day at the Cave.
I sanded the dihedral brace and glued the trailing edges, both the centre section triangle stock and the pre-formed curved sections in the aileron bays.







Cheers,
Eran
Old 07-26-2020, 03:52 AM
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Since large blocks of hard wood are not easily found at the hobby shops here, I laminated three pieces of Tasmanian Oak and will cut it to size for the landing gear blocks.
I am also making some progress on the detachable wing tip idea. While not final, I am experimenting with locating dowel and birch plywood tongue that will correspond to a fixed plate with a lock nut to be located between the last couple of ribs. A screw will then fix the wing-tip in place.
While at it, I got the laser cut parts that form the round wing tip and started gluing them together.












Cheers,
Eran
Old 07-27-2020, 02:10 AM
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I glued together one wing-tip. I also glued the plywood sub-ribs which reinforce the landing gear blocks and the front wing-bolts plywood supports.






Cheers,
Eran
Old 07-28-2020, 02:26 AM
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I was working on the wing-tip today. I reached the point of decision regarding my "additional ribs" as I am attempting to make it removable.

One of my concerns was the fact that on the wing-tip side I was using 2mm Lite-Ply rib which is flexible and may curve and create an untidy contact area with the last rib on the centre section (a stiff 3mm Birch Plywood).
I decided to supplement the original design 3/32" sheet balsa support at the TE with two 2mm Lite-Ply pieces. I had to be careful not to block the hole for the carbon fibre rod (which may be used as the aileron hinge). I glued the two supports while the rib lay flat on the table.
My next obstacle was the spruce spars. I could not see an easy way to bend them to fit the wing-tip. I replaced them with balsa spars which are plenty strong for this small section. I could not bend the Balsa spars all the way as well, but at least by using doublers I will be able to sand them to shape towards the tip.
Last, I glued the sheer webs.













Cheers,
Eran
Old 08-05-2020, 03:45 AM
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Slow progress again, but progress.
I glued the landing gear blocks into place and am still working on the wing-tips retention system.










Cheers,
Eran
Old 08-06-2020, 03:13 AM
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Keep chipping at the work required on the wing.
I started work on the second wing-tip, gluing the pairs of balsa laser cut parts.
I also completed the main spar shear web on one side of the wing and the plywood shear web (3 bays following the dihedral brace) on the other side.









Cheers,
Eran
Old 08-10-2020, 03:26 AM
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Progress on the second removable wing-tip, a repeat of the work done with the other one.







Cheers,
Eran
Old 08-10-2020, 05:39 AM
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Looks like you are doing a great job of building. Boy there is allot of lumber in this thing.

Bob
Old 08-10-2020, 03:45 PM
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Thank you Bob.
Yes, there is more wood in this build then any other aeroplane I scratch-built before (of similar size), however, there is also more wing area which I hope will make it fly well.

Cheers,
Eran
Old 08-11-2020, 03:25 AM
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Originally Posted by erans View Post
Thank you Bob.
Yes, there is more wood in this build then any other aeroplane I scratch-built before (of similar size), however, there is also more wing area which I hope will make it fly well.

Cheers,
Eran
Just out of curiosity, what do you think the all up empty weight will be?

Bob
Old 08-11-2020, 06:24 AM
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Bob - To be honest I am not sure. It won't surprise me is it will be 7.5kg - 8kg. It will require a Heavy Model Inspection (in Australia it is required for all aeroplanes over 7kg).

Today I only got couple of lock-nuts into place for the wing-tips retention. It allowed me to see the full size wing for the first time. It is a long wing...



Cheers,
Eran
Old 08-11-2020, 12:26 PM
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Originally Posted by erans View Post
Bob - To be honest I am not sure. It won't surprise me is it will be 7.5kg - 8kg. It will require a Heavy Model Inspection (in Australia it is required for all aeroplanes over 7kg).

Today I only got couple of lock-nuts into place for the wing-tips retention. It allowed me to see the full size wing for the first time. It is a long wing...



Cheers,
Eran
if you are at 8kg you will have a wing loading of 30.2 and a cubed loading of 9.9, not bad. What engine/electric motor are you going to put in it?

Bob

Old 08-11-2020, 03:52 PM
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Bob - I will probably be using the MVVS 40 IFS (40cc), but also have a DLE 35RA on the shelf if I will think it will be a better option. The plans call for the Quadra Q35.

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