Justin's Raven Build (now engine change)

The Raven type of aircraft.

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heisan
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Fri Aug 08, 2014 4:09 pm

OK - Installing the engine tomorrow! I think everything is pretty much done. All the cables are made up, and tested. Probes and senders fitted. Exhaust (almost) fitted. Wiring (mostly) complete.

There will still be a bit of work to do once the engine is in, but at least it will be on the plane...

Cowl jigs made up to space and align cowl to prop/spinner:
rps20140808_155204.jpg
I noticed a mismatch between the ASI on the Ultra and Xtreme, so I converted a table leg to a water manometer to do the calibration:
rps20140808_155344_374.jpg
Turns out the Ultra was spot on, but the Xtreme was off. Seems someone did a factory reset on the Xtreme, and wiped the calibration. Calibration now set, and both agree with the water manometer from 0-100kts.
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Justin Schoeman

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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Tue Aug 12, 2014 10:32 am

No pictures from Saturday - I was way too busy, but a friend did get some, and I will add them when I get a chance. The engine is on the airframe now, and mostly hooked up. Everything is looking good, except for the top cowl, which is 50mm too short (Raven front fuselage-firewall intersection is different from the 601).

Will be ready soon!
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Mon Sep 15, 2014 10:07 pm

Wow - I have been very lax in posting updates recently. Between customers baying for my blood (or at least for my work-product) at work, working 3-4 hours every evening on plane parts and 8+ hours every Saturday and Sunday, I have not had much time.

Fortunately, tonight I am absolutely stuffed from squash training, and don't actually have much to do on the plane, so I will spend some time posting the updates.

As usual with this sort of work though, there is a lot of work, with very little to show for it, but here it goes anyway...
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Mon Sep 15, 2014 10:16 pm

First, fit the cowl, with clamps, centring everything on the prop hub, and positioning with fibre tape:
rps20140915_201703.jpg
rps20140915_201822_229.jpg
Once everything looks good, the bottom cowl is drilled, and screwed to the fuselage (you can also see how the top cowl has been extended - by Arthur - so that it now fits):
rps20140915_201946_631.jpg
Once that is all done, the top cowl is trimmed to fit flush, then bonding/reinforcing strips epoxied in, hinges flocked and riveted in place, joggles formed, and NACA duct cut in and bonded. One sentence that took a solid week of work to complete...
rps20140915_202434_205.jpg
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Re: Justin's Raven Build (now engine change)

Unread post by Induna » Mon Sep 15, 2014 10:32 pm

It is looking great! I am interested to see the performance of this engine. I have the Rotax 100HP installed and the aircraft is a rocket, giving me 1300 fpm at sea level. I think you will have excellent performance!! :)

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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Mon Sep 15, 2014 10:35 pm

Next was the exhaust. I was not 100% sure how to do this. Cutting those big holes out with a dremel was just not working, Neither was drilling out the 30 18mm holes in 1.6mm stainless steel for the tailpipe. That stuff is tough! Fortunately, someone mentioned that they had the holes burned through at an exhaust shop - so I thought I would have a look-see what a TIG could do. The tests on some scrap stainless looked perfect, so it was time to try on the real thing. 180A in one spot resulted in a nearly perfect hole of around 18mm in diameter. So for once I managed to put my best welding skill (burning holes through anything I try to weld) to use... A few minutes later, and all 30 holes were neatly burned through. A little work with a grinder cleaned them up and removed the slag. Unfortunately, I forgot to take pics of the tail pipe, so you will have to take my word for it! (I did learn an important lesson here though - when you crank up the amps on the welder, remember to set the helmet to shade 15! Doh!)

The muffler was easier, being of relatively thin steel. A steady hand and a low current, and I could cut out a fairly (round) hole...
rps20140915_202034_305.jpg
Repeat on the other side, and out to the air field for a trial fit. Perfect:
rps20140915_202149_912.jpg
Tack it in place with some epoxy, and then back home for welding:
rps20140915_202329_467.jpg
In the end (as usual for me, welding thin sheet to thick, I spent more time chasing and filling burn-throughs than actual welding. So in the end, I just tacked it (as above) and took it to Noise Boys for a full weld. Really wish I had just finished the job myself - the Noise Boys weld looks mechanically sound, but is ugly as sin. Fortunately no pictures...
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Mon Sep 15, 2014 10:46 pm

The last fairly time-consuming bit of work is the baffle to duct the standard Jabiru oil cooler to the cowl (which was intended for the oil cooler that Jabiru Australia uses). Here is a picture of the basic frame:
rps20140915_202242_813.jpg
Making the sides ended up more difficult than expected - so I just wrapped the whole thing in fibreglass. No finished pics, but it looks quite good, and fits perfectly.

And finally the finished product:
rps20140915_202512_581.jpg
Actually, not the finished product yet - the factory sent me the wrong prop bolts, so it is just tacked together for show. But SOON!

Hopefully get the new prop bolts this week, and do some test runs over the weekend. Inspection the week after, and away we go!
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Mon Sep 15, 2014 10:58 pm

Induna wrote:It is looking great! I am interested to see the performance of this engine. I have the Rotax 100HP installed and the aircraft is a rocket, giving me 1300 fpm at sea level. I think you will have excellent performance!! :)

Jacques

I am also looking forward to this! The numbers say I should get around 1300fpm at 540kg at 5000' (or 1800fpm solo!)- but the numbers may be a bit optimistic. Also want to see what cruise speed will be like. Could get it up to about 95KIAS on the VW - hopefully the Jab will get me up to about 110KIAS without burning too much fuel...
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Re: Justin's Raven Build (now engine change)

Unread post by Induna » Mon Sep 15, 2014 11:05 pm

110kts, isnt it close to Vne? I can cruise around 110mph burning around 20lph, but i have the standard wing.

Let us know the performance figures. She look pretty with the new longer cowl...
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Mon Sep 22, 2014 10:47 am

Just told Giel that I think something is wrong with the engine. Started on the first blade, and settled straight into a silky smooth idle at 750rpm! Very un-Jabiru behaviour. Quite, and smooth a silk - can't wait to get it airborne!
rps20140921_193237.jpg
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Re: Justin's Raven Build (now engine change)

Unread post by Jean Crous » Tue Oct 07, 2014 9:48 pm

:D Hi Justin , you flying yet ?
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Tue Oct 07, 2014 10:18 pm

Not yet. Trying to coordinate with AP for inspection - then paperwork, and fly!
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Sat Oct 11, 2014 11:54 pm

AP inspection this morning, and all is perfect. CAA paperwork this week.

Software glitch on the Xtreme means I cannot swing the compass - hoping that MGL can help out this week, as this will be the last legal requirement for a test flight.
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Sun Oct 12, 2014 8:58 pm

The entire exercise added 1.4kg to the aircraft. New empty weight is 284.5kg. CG is perfect now. Previously I was flirting with the rear limit 2 up. Now, full fuel, and I require a minimum of 62kg total in pilot+pax seats for the forward limit. Emty fuel, 90kg in each seat, and I can still put 30kg in the baggage compartment before reaching the rear limit. So basically, it is pretty much ideal now.
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Re: Justin's Raven Build (now engine change)

Unread post by heisan » Mon Oct 20, 2014 11:48 am

First attempt at a test flight was on Saturday morning. The poor test pilot got a decent cardio workout when the EGT alarm went off soon after take off. He did the right thing, and did it tight circuit to land back again.

Unfortunately, for some reason, the Xtreme did not create a data file for the flight, so I have no real numbers on what went wrong. All I could really see were the high water marks on the CHT and EGT guages. CHTs were all green, but the #1 bank EGT was about 30F into the red (#2 bank was still green). EGT imbalance is a fairly common issue with the Zenith FWF kits. I tried one solution (that has worked for at least one other builder) of using a smooth, wide radius curved tube from the air box to the carb.

Without the data recordings, I have little to go on though, so not quite sure where to go from here.

Part of the problem may be that the test pilot did a partial throttle take off. With the jabi, this can result in an excessively lean mixture - so the solution may well be to just take off at full throttle.

Aside from that, there may well be another issue. The test pilot says that he was climbing out in the yellow arc (ASI) - meaning above 105KIAS - and this wasn't even at full throttle! There could well be an issue with exceeding Vne in level flight (a big no-no for issuing the final ATF) - so I may need to look into ways to slow it down a bit!

Take off video:
https://www.youtube.com/watch?v=vU4owyz9X-o
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