Justin's Raven Build (now engine change)

The Raven type of aircraft.

Moderator: Moderators

User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Sun Oct 26, 2014 9:54 pm

OK. Did some work, but Wx prevented further test flying.

1) put a vertical flow divider in the induction pipe
2) figured out how to get MGL Xtreme data recording working (turns out you need to switch recording off and back on, if you replace the SD card).

Did some brief engine runs. CHT limits preclude any extended full power runs, but got this plot:
temps.jpg
Can see the following:
1) always starts immediately and settles into a smooth idle at 730RPM.
2) EGTs are well balanced at low power and at full power. Seems to be some divergence at around 2000RPM - but no idea how they would settle with time.
3) Full throttle RPM just a hair shy of 3000.
4) MAP (in mb) - can see the induction restriction is quite bad, but apparently normal for Jabs.
You do not have the required permissions to view the files attached to this post.
Justin Schoeman

ZU-FSR (Raven)
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Mon Oct 27, 2014 11:10 am

And to top it off, MGL just sent a bugfix for the Xtreme, so hopefully the compass will also work correctly now.

Nearly there!
Justin Schoeman

ZU-FSR (Raven)
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Sun Nov 02, 2014 9:52 pm

Bah - another aborted test flight on Saturday when the oil pressure spiked (on the ground still). Stripped and cleaned the PRV - but no obvious issues found. Will do extensive ground testing next and see if I can replicate it :( .
Justin Schoeman

ZU-FSR (Raven)
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Fri Nov 21, 2014 10:42 am

Anybody else getting slightly peeved with this weather? Seems flyable weather and test pilot availability are a rare combinations :( .
Justin Schoeman

ZU-FSR (Raven)
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Mon Dec 01, 2014 2:38 pm

OK - Finally got a test flight in on Saturday morning. Unfortunately, the MGL for some unknown reason decided not to record the flight data (the Xtreme works perfectly, but flight data recording seems remarkably unreliable for some reason).

I have got the basic numbers though, and it looks good! Still have some work on the EGTs though, with a 100C imbalance swinging left, to right and back again at various throttle settings. CHTs are good - highest was 182C on #5 in a partial throttle climb - but generally all are around 160C, or less.

Take-off run at around 480kg was ~350m. Climb out at 80KIAS is 800fpm (Vy is around 65KIAS - so there is still a lot more in the bank, if you like looking straight up into the sky).

Still need to figure out optimum cruise. Seems most comfortable at around 95KIAS at 2850RPM (17" MAP). Full taps gives 107KIAS at 3270RPM (22" MAP).

Prop needs some work, as I am a little close to red line at the moment (full throttle, straight and level).

I am trying to order another 4 EGT probes from MGL at the moment - would like to instrument all 6 cylinders and see what is happening with those wild EGT swings. Will hopefully take leave sometime this week to install them, and test again on Saturday.
Justin Schoeman

ZU-FSR (Raven)
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Wed Dec 17, 2014 10:14 pm

Still fighting with temps. I have now installed EGT probes on all cylinders, so I have a much better idea of what is going on. Turns out the main problem is at full throttle, where there is little turbulence from the butterfly. In this condition the EGTs just go crazy. Len has a simple solution though - just close the throttle a tiny bit, and everything will come right.

#5 CHT was also borderline, but I think I may have it sorted now. Fitted some inter-cylinder baffles (formed on top of the cylinders, but installed underneath):
rps20141215_124103_794.jpg
Makes a massive difference on the ground runs - still need to see what it does in the air though.

Unfortunately, until I have the temps safe, the test pilot will not sign it out. So this testing is horribly slow. Need to wait for a weather break + test pilot to be available at the same time. And now he is away until January - so will not be much more progress until then.
You do not have the required permissions to view the files attached to this post.
Justin Schoeman

ZU-FSR (Raven)
Jean Crous
Tree Tousand
Tree Tousand
Posts: 3449
Joined: Tue Mar 02, 2010 10:10 pm
Closest Airfield: FASX
Location: Barrydale Western Cape
Has liked: 346 times
Been liked: 167 times

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

Unread post by Jean Crous » Mon Jan 12, 2015 7:48 pm

:D Meneer ! How are you doing, and last but not least how is the aerie doing ?
Regards
Jean.
Cubby Aircraft Factory
Suppliers of Nitrate, Butyrate, Adhesive, Fabric.
New front seat solo Cubby Renegade
Cell : 072 6716 240
SACAA Approved Person 402
Email: cubbyaircraftfactory@gmail.com
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Mon Jan 12, 2015 8:05 pm

Cyril has been away since my last post - so no news yet. Hopefully resume test flying on Saturday.
Justin Schoeman

ZU-FSR (Raven)
Jean Crous
Tree Tousand
Tree Tousand
Posts: 3449
Joined: Tue Mar 02, 2010 10:10 pm
Closest Airfield: FASX
Location: Barrydale Western Cape
Has liked: 346 times
Been liked: 167 times

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

Unread post by Jean Crous » Wed Jan 21, 2015 7:23 pm

:?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?:
J
Cubby Aircraft Factory
Suppliers of Nitrate, Butyrate, Adhesive, Fabric.
New front seat solo Cubby Renegade
Cell : 072 6716 240
SACAA Approved Person 402
Email: cubbyaircraftfactory@gmail.com
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Thu Jan 22, 2015 12:04 am

Jean Crous wrote::?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?:
J
Yeah. Don't ask... EGTs are OK now, but now with higher temperatures, I am chasing high CHTs :( :( :( .
Justin Schoeman

ZU-FSR (Raven)
Jean Crous
Tree Tousand
Tree Tousand
Posts: 3449
Joined: Tue Mar 02, 2010 10:10 pm
Closest Airfield: FASX
Location: Barrydale Western Cape
Has liked: 346 times
Been liked: 167 times

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

Unread post by Jean Crous » Thu Jan 22, 2015 8:42 am

Ai ou Justin, ............al daai werk en dan moet jy NOG sukkel :( But I know you will get it sorted 8)
Jean.
Cubby Aircraft Factory
Suppliers of Nitrate, Butyrate, Adhesive, Fabric.
New front seat solo Cubby Renegade
Cell : 072 6716 240
SACAA Approved Person 402
Email: cubbyaircraftfactory@gmail.com
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Sun Jan 25, 2015 8:02 pm

OK - tried every trick I could find today - all in one go. Added ramps over the vertical plates in front of #1 and #2. Drilled the air dam above #3 and #4 into swiss cheese. Added lips to the cowl exit area.

Not sure which worked, but temps are OK now. With an OAT of 27C, I climbed 1000' with the highest temp at 175C. Temp was fine at all cruise settings, and only 165C at best cruise (2750RPM, 88KIAS).

Still some work to do. #1 and #2 are too cold, so I need to raise the ramps a bit. #4 is also a bit cold, so cut away some of the air dam. But at least I can safely fly the plane now.

EGTs are OK ish. They go all over the place at full taps, but Len says this is normal. Just reduce throttle a hair and they all come back. At cruise settings, everything is pretty even.

All in all, I think I am getting there.

Booking an extended session with Cyril next Saturday to get some rust off - need to learn to land this beastie again ;) .
Justin Schoeman

ZU-FSR (Raven)
User avatar
Zak
Mags Dead Cut
Posts: 64
Joined: Tue Sep 30, 2008 7:35 pm
Closest Airfield: Eagle Creek
Location: Pretoria
Has liked: 0
Been liked: 1 time

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

Unread post by Zak » Mon Jan 26, 2015 6:33 am

Well done Justin!!!!
Taylorcraft BC-12D ZS-VHL
Jean Crous
Tree Tousand
Tree Tousand
Posts: 3449
Joined: Tue Mar 02, 2010 10:10 pm
Closest Airfield: FASX
Location: Barrydale Western Cape
Has liked: 346 times
Been liked: 167 times

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

Unread post by Jean Crous » Sun Feb 01, 2015 6:48 pm

How is the flying doing..........or is the weather keeping you on the ground :?:
Jean.
Cubby Aircraft Factory
Suppliers of Nitrate, Butyrate, Adhesive, Fabric.
New front seat solo Cubby Renegade
Cell : 072 6716 240
SACAA Approved Person 402
Email: cubbyaircraftfactory@gmail.com
User avatar
heisan
Six Tousand
Six Tousand
Posts: 6055
Joined: Mon Sep 19, 2005 3:45 pm
Closest Airfield: Rhino Park
Location: Pretoria
Has liked: 40 times
Been liked: 344 times

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

Unread post by heisan » Sun Feb 01, 2015 7:17 pm

Had a decent session for Cyril on Saturday morning. Did a couple of circuits at Zynkraal, then Kitty Hawk, then Rhino Park. Then a couple of solo circuits at Rhino. Getting the hang of this flying thing again ;) .

Had a nasty run in with the weather on Saturday afternoon though. Wanted to test a tweak to the baffles before going home. Checked the weather radar and all the visible cells were moving away, and made sure I had visual on the ones that were nearby. All looked good, so off I go... At around 300' I got slammed by incredible wind shear. Although the cells were far away, and moving away, the squall winds from one of them had hit the airfield. Suddenly the wind socks are straining at the masts in a 45 degree cross wind, and some very excited instructors are on the radio suggesting I head to Wonderboom. I thought I would give it a go, and see if I could get in at Rhino before diverting. Had a ground speed of around 140kts on downwind (which for some obscure reason went by in a flash). Final approach was at 75KIAS with about 20 degree crab angle (which works out to around 25kt cross wind component) and pretty bumpy. The short wings absorb the bumps nicely, and this plane is responsive - so I continued the approach, with the plan to go around, and head off to FAWB if at any point I didn't like it. Round out and was OK - only took about 3/4 rudder and 15 degrees of bank to keep it lined up, and still had plenty of control, so I carried on with the landing. Wasn't my best landing of the day - but wasn't my worst either. At least now I have one of the test flights done 'max demonstrated cross wing component: 25kts' ;) .

And after all that, trimming the baffle didn't help. #4 is still running too cool, so I can trim a bit more off next time.

Today, when the weather radar showed a few active cells around Rhino Park, I decided to rather stay at home...
Justin Schoeman

ZU-FSR (Raven)

Return to “Ravens”