ghealey

Hello Marcus,

The new picture of PT OTB is of great assistance, thanks. I am currently adding cabin detail and will try my hand at making a full length pilot. I hope to have all the fine detail finished for some scale competitions in September.

Kind Regards

Geoff

Kellermann

Geoff,
send me your e-mail address so I can send the pic in a bigger size, I think that the RCU window reduces them a lot.
On the full size pic you'll be able to see the Tike Bazaia tail logo clearly. Also check the www.tikebazaia-airshows.com.br site for the correct phone # which is shown but not clearly on the pic. Have you replicated the different rear window?

Marcus

flying skunks

My Feedback: (7)

Hello Guys,
I had to fabricate my own landing gear to allow for the 30" prop. It's great going to a field and pull out the biggest darn Decathlon that most everybody else has seen, watching a 40% aerobat hover, and pull up next to him in a hover (a silent hover) next to him. Lots more practice and flying to do.Been thinking of entering an IMAC compition with PT-OTB
Donnie

Kellermann

Hey Donnie,
where are the pix?? I sure am curious how your model came out...
And the guys as well!!!

Marcus

apalsson

My Feedback: (1)

Hi all,

I was looking at different ways to mount the engine in the SD and was wondering about the merits of building a box rather than mount on stand-offs.
I was thinking that with a good engine box, you were guaranteed a straight surface to bolt the engine against where as if I use stanoffs, I run a risk on the spacers being slightly uneven.
Wouldn't a box also be easier to set for the desired down and right thrust?

Any comments?

Regards

Ari

Kellermann

Ari,
I think that is a good idea, many designs use this arrangement. Just make sure the box is firmly anchored to the firewall, best would be cutting a rectangular opening into the firewall thru which you'll insert the box from behind (fitting snugly) and epoxy it in.
Even better would be drilling some holes thru which you can insert some pins or screws to lock it in place.

Any pix of your model?

Marcus

apalsson

My Feedback: (1)

Hi Marcus,

This was exactly what I had in mind. Build the box and cut a hole in the firewall where I would fir the box through. Epoxy it in place and pin into the firewall.

I suppose the walls of the box wouldn't have to be as thick as the front or as the firewall itself?

I'll try to take some photos on the weekend and post them.

Best regards

Ari

Kellermann

Ari,

consider the box as an extension of the firewall itself. The front part should be as thick as the firewall just to hold the nuts and bolts to keep the engine safely attached to the airframe. But the walls don't have to be that thick, I think you can use some 3/16" ply - but, at the other hand, safe is safe, if you have enough ply to make the box from the same material as the firewall itself, why not go for it? Better too strong than too light.
Besides that, instead of some dead weight one will most likely need on a short coupled airplane, it's better to have some useful weight up front.

Just to make it clear about the strenght of the box: on a long nose bird such as a Zlin 526, I have seen the box walls made of balsa and the front wall of ply, everything fiberglassed. Should make a light and strong box - of course, the lighter the better because a Z526 has a real long nose...

Wish you luck with the box.

Marcus

apalsson

My Feedback: (1)

Marcus,

The firewall is 12mm (1/2") and I have some 6mm ply. I was going to construct the sides from 6mm and laminate two layers of 6mm for the front part.
If I interlock the sides, this should be plenty strong, as the length is not much more than 2 inches.

Regards

Ari

ghealey

Ari,

I got a mount turned down from a solid piece of aluminium. The top is flat and the inside hollowed out. This is good for the Zenoa because of the crankshaft extension. The bottom of the mount has a outer rim that is bolted to the firewall. I had this made for my Chester Jeep and I needed to use an extension for the SD.

It has work a treat for both models.

I plan to use the same method for my ZDZ80 in a Extra 300. I will remove metal from the side to allow air to the carby.

Regards

Geoff

Kellermann

Geoff, your method is as good as the other one, although you need either a lathe and machinist's knowledge or buy the service of a specialist. Looks very professional, indeed.

Ari, go ahead with the 6mm sides which is about 1/4" for our "imperial" fellas. Best of all, make the box so that it tapers to the front. If you bevel the inner edges of the rectangular cut through the firewall, it should be a natural lock. Also make the box as big as possible so the forces are spread over a wider area.

I have a sport model (which looks like a SD in the air) and I had originally built a box but not recessed into the firewall, and it came loose after a couple of months, even being secured with screws from behind.
Then I replaced the engine AND the mount, I cut 2 lenghts of 5x12mm aluminum (dural), that's about 3/16 x 1/2", and bent it according to the photos below, drilled holes to bolt on the engine and then onto the firewall, looks like a "spider" but is truly effective - and I put some hard rubber grommets between it and the firewall to absorb some of the vibration.
I am flying the whole season without one single loosening of any bolt.

Hope this helps.

Marcus

ghealey

Hello Marcus,

What a great idea! Your method is very simple but effective. I will try this method on my ZDZ80. I will not have to worry about airflow to the carby.

You are correct, an engineer friend of mine has access to a lathe and mill and both were required to make my mount.

Regards

Geoff

Kellermann

Hi Geoff,
yup, simple and effective. Know what? It's actually a barbecue spike that I bought at the supermarket and cut down to size...hahaha

Donnie, I see you're online, are there any pics of your "flying machine" ??

Marcus

flying skunks

My Feedback: (7)

Marcus,
I have earlier pix of the Decathlon,but someone had to post a new picture of PT-OTB with lettering on the side that I thought looked aewsome, so back to doing more painting.
Donnie





Ididn't know there was a different kind of plane! And the plane doesn't know that it's windy!

Kellermann

Well Donnie, that "someone" happens to be myself...I also thought it looks awesome, though I think Tike Bazaia exagerated a little on the rudder...
Good luck with the "new" paint job and then let us see the pics.

Marcus

Kellermann

Hey Fellas,
specially Donnie, Sam, Geoff, Ari - all PT-OTB fans

Here go some additional pix for you.

MArcus

Kellermann

Here goes another bunch
Marcus

Kellermann

And yet another one.
Marcus

apalsson

My Feedback: (1)

Thanks for the photos Marcus, they are excellent !!

apalsson

My Feedback: (1)

Hi Geoff,

Very smart and professional way of mounting the engine.
I don't have access to a mill or a lathe, so for now, I might have to stick with a plywood box. I am going to build it tapered and slide it out through a rectangular hole in the firewall. If I pin it into place as well as some 45min epoxy, it should be quite strong.

You mentioned an Extra 300 with a ZDZ 80?
Any details?

Regards

Ari


PS: I go to Melbourne a fair bit for work ... would love to see the SD up close one day

apalsson

My Feedback: (1)

Guys,

Having been looking at the full scale photos from Marcus and others, I'm not as happy with the tail wheel bracket I used as I used to be.
I saw Ken used a home made bracket that looks more scale. Mine is a standard CF bracket from Graupner.

Any details of a custom made bracket where I could shamelessly borrow others' designs?

Kellermann

Ari,
why don't you use the one from Klett?
A pic goes below.

Better yet would be a "Scale Aviation" unit - it's said they're countrymen of yours, Apache Aviation in UK ist their european agent.

Sorry, I don't have a pic but they have Scott 2000 and Lang tailwheel units, which can easily be adapted for a doublefork like on the SD.

Marcus

apalsson

My Feedback: (1)

Hi Marcus,

Do you have any web address or other details for Scale Aviation?
If not, I have had a dialog with Mike Clewes from Apache Aviation. I bought my Super Chipmunk from them.
Most helpful people.

The "Klett" unit looks very much like one I used for my 1/4 Taylorcraft but it came from Thunder Tiger. I suspect it is a bit small for the SD?

Ari

Kellermann

Ari,
I am sorry but the only info I have is a small note on one magazine, no web address - I tried to find but wasn't lucky, at the Apache site I could not find any reference to the Scale Aviation tailwheel assembly.

Yeah, I think the Klett is rather small altough I thought they have a giant scale one...

Marcus

ghealey

Hello Ari,

The Extra is a 330S from Model Design in SA (http://www.modeldesign.com.au/). It is 92 inch in span. It has a glass fuse and sheeted foam wings, stab and rudder.

The glass work is quite good and it should be pretty well matched to the ZDZ80.

I am swapping work between this and the GeeBee R2.

If you like give me a call when you are in Melbourne, maybe we can get together for a coffee.

Regards

Geoff