What did you do on your airplane project today?

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Marc W

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Mar 31, 2017
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Completed another step in improving my Jabiru 3300 cooling system. I have been working on the left side cooling plenum. Cylinder #6, last cylinder on left side, was originally the hottest cylinder. I previously closed up a couple of gaping holes in the aft end of the plenum. Doing that brought #6 CHT in line with the four outside cylinders. Cylinder #4, middle cylinder on left side, became the hottest cylinder and it ran 60 to 80 degrees above the outside corner cylinders. I don't believe I have enough cowl exit area for hot weather. However, the air entry at the front of the plenums is choked down. This is the entry to the right side plenum. See how the top of the plenum hangs down into the cowl inlet.

Right Plenum Entry.jpg

The left side air entry was similar plus the left side plenum is smaller for some unknown reason. I therefore reworked the left side plenum to open up the air entry. The new look below. I may need to cut the air dam in front of the cylinders down but I am going to fly it like this first. We are well into fall weather and there is snow on the mountains so I won't be able to test it in hot conditions until next summer. I still hope to see more uniform temperatures across the cylinders. Its all buttoned up and ready to fly tomorrow.
New Plenum Entry.jpg
 

Marc W

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Mar 31, 2017
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948
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Colorado
Flew for 1.5 hrs. this morning. It was to cool to tell if the plenum mods made any difference. Temps in the 50's F. on the ground. Icy at altitude. The fall colors are a couple weeks late this year. The quakies are just starting to turn and the oak brush is still green but it is still pretty. Cruising at 11,500' over the Grand Mesa, the largest flat top mountain in the world!
Fall.jpg

I also changed the air deflectors that go under the gaps between the cylinders. My new, enlarged and hopefully more effective part on the left and the modified stock part on the right.
Gull Wings.jpg

I also got a good read on fuel consumption this morning. I filled before the flight, flew for 1.5 hrs. and top off after the flight took 6.3 gals. 4.2 GPH including climb from 5,200' to 11,500' in a Rans S-7 with Jabiru 3300. That doesn't seem to bad to me.
 

Toobuilder

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Mojave, Ca
Just because I apparently have some form of disorder...

IMG_20221002_151232842.jpg

...I'm experimenting with a new induction airbox configuration.

The keen observer may notice that this filter air box (FAB) was my original unit, positioned between the long pitot scoop on the lower cowl and the SDS throttle body mounted to the sump in an updraft configuration.

Well, I butchered that FAB and it is now bolted directly to the sump, still contains the filter, but now mounts the TB on the front in a horizontal position. Why do this when I just spent a bunch of time fabricating another scheme that feeds from the cooling inlet? Couple of reasons.

1. This is a quick way to validate a similar scheme for my eventual change to the "tuned" angle valve sump.
2. It saves several inches of depth on my lower cowl, so hopefully I will reap some aero goodness when I rework the cowl AGAIN.
3. It will provide a very easy method to further validate the difference between the cooling inlet induction and pitot style (yep, I plan to cut a hole in the cowl and throw a pitot out the front to compare)
4. I have some form of mental disorder that wont let me stop. Its like the Winchester Mystery House without the black magic and witchcraft.
 
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Map

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Dec 29, 2020
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137
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California
If yu want to check your engine cooling on a cold day, simply add the temperature difference between the actual OAT and the OAT on a hot day to your engine temperatures to see if it would be too hot. Only works if there is no thermostat in the system.
 

Marc W

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Mar 31, 2017
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948
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Colorado
I flew with my new Meglin prop for the first time this morning. I like it. I didn't have quite enough pitch in it so I increased it after the flight. It is much smoother and quieter than the cut down Sensenich that was on the plane. I won't know if performance is any better since I never tried to optimize the pitch on the Sensenich.

It is another cool day so hard to tell on the cooling. The CHT spread is narrower with the reworked plenum so maybe it was worth it.

Meglinsky Prop.jpg
 

dwalker

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Mar 6, 2021
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Tennessee
The last few days has had at least some activity on the Dragonfly. In no particular order-
Parts have been ordered and some even delivered to make a CNC hot wire cutter so the elevators, ailerons, and rudder cores can be cut. Been working my way through the software to turn the drawings into G-code,
cut out all the various fabrics- BID, E-glass, and carbon twill- for the various cockpit bits not yet laminated. It was a 4 hour project that drug out a few days because-
In the interest of strength I added layers of carbon to each side of the "instrument tray" and the half bulkhead. This area has to be very stiff and strong because the hinges for the canopy attach to it
After it was all cut out decided to use a veil fabric to save some finishing time on the armrests and side panels, then discarded that idea as I had some carbon offcuts I could use for the appearance layer.
The plan was to vac bag the panel, then not, then OK just go ahead and bag'em... but then...
As I was prepping this morning I got a wild hair to use the less expensive West epoxy I have for the non-critical bits vs using the MGS epoxy that is being used everywhere else. For whatever reason it never occurred to me to see which Hardener for West I had on hand and so about 3/4s of the way through slathering runny micro on the foam it became apparent the cup was getting warm, but its kept in a hotbox at 95deg, so moving on...
Pumped out a bit of pure epoxy and started the first layer of BID on two panels, and pretty quickly noticed the cup was HOT and the epoxy was starting to kick. Yeah, thats right, only hardener on hand for West is the "Fast".
Not being sure if the MGS will react poorly to the West, the parts with the BID layer on them were peel plied to cure up and I'll use MGS with the right SLOW hardener tomorrow.
Additionally, all the remaining spruce plywood came in to make the hinge attach points and will have some fun with the jigsaw and sander later.
 

Marc W

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Mar 31, 2017
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948
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Colorado
Flew the Rans S-7/Jabiru 3300 with the new Meglin prop after putting a little more pitch in it. It took about 9 minutes to climb from 5200' on takeoff to 10,200' so it averaged better than 500 fpm. I timed it at about 600 fpm right after takeoff. The engine is rated at 3300 rpm continuous and I am running 3000 rpm in climb. Temps were all good so I am going to fly it a while at this pitch setting. It was cool, temp was 14c. at takeoff.

The sawed off Sensenich was so loud that it was unpleasant to run full power even with a noise cancelling headset. The Meglin scimitar prop is an order of magnitude quieter. It makes flying the airplane fun! The Sensenich also had an annoying vibration that is gone now. The Meglin prop is worth it for the smoothness and noise reduction alone.
 

pylon500

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Dec 26, 2003
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Taree Airport Australia
Having to spread myself around all the different projects (wife's household ones as well), but got to do a run of mass production, machining the tops of the MLG strut.
A 1000lb mono-shock strut is attached to the top of the strut inside the MLG leg. The square groove around the fitting will have a PTFE/bronze guide wrapped around it to run inside the alloy leg.
Strut_tops.png
1K_strut.png
PTFE:bronze.png
 

Kyle Boatright

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Marietta, GA
There is a history of cracked gear mounts on RV-6's around the sockets where the tapered rod gear mounts. Mine developed those cracks sometime back and I committed that I would take care of the problem this fall. Well, fall is here and it is time. So the engine, gear, and engine mount had to come off. Last evening and this morning I spent about 6 hours prepping everything for removal - taking wires and hoses loose, pulling off a bunch of zip ties and Adel clamps, pulling the cotter pins that secure the engine mount to the firewall and the engine to the engine mount. I did such a good job, I don't even have a nasty cut anywhere.

So just after lunch today, a buddy came by (bringing the 2nd engine hoist) and some platforms he built for me (it is good to have friends) and we removed the engine, gear legs, and engine mount in an hour and a half or so.

The airplane is resting on a couple (actually 3) 16" high platforms to level it and keep the belly antennas off the ground. There are carriage bolts threaded into the tie-down ring mounts. The carriage bolt heads rest on the platforms.

Here's the result:RV6 No Gear.jpg

The next step is to clean up the mount, strip the areas that need remedial work, bead blast them to be sure they are clean, and deliver the engine mount and gussets to someone who will weld the cracks and add the gussets I bought from Vans.

I'm guessing I'm 20, maybe 25% of the way towards finishing this little project...
 

Kyle Boatright

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Do you have a list of "while I have it open ..." tasks?


BJC
I'm probably gonna replace the engine isolator mounts (they are 20 years old and have 1300-1400 hours on 'em. I've had a new oil cooler sitting on the shelf waiting on this opportunity, and I'm also gonna replace the breather hose while I'm in there. I'm considering having new oil and fuel hoses made since I had to pull them too. They are "lifetime" teflon lined hoses, but 20 years is a pretty good run.

I'll also give the firewall and back of the engine a good cleaning.

What have I forgotten?
 

gtae07

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Dec 13, 2012
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2,397
Location
Savannah, Georgia
Fitted and aligned the leg fairings
Faired in the step at the wheel pant joint
Laid up rough lower intersection fairings
Put her on her own gear!
Cleaned up the shop some
Hung the engine, for good this time! 🥳
Started trimming the upper cowl

All the effort going into fiberglass and it's still only netting a 20ft finish. Oh well. I'm about to the point of just saying *******it, hitting the glass with rattlecan, and proceeding to flying unpainted till I can get a paint slot somewhere. Fit/finish/prep is going to drive me nuts--I'm just happy I'll soon be working with metal (baffles) and hoses/wires again soon. Much more satisfying.
 

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gtae07

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That's the as-received finish on the Van's parts. Up close the cowl is a pinhole disaster. My scratch-made parts are cleverly hidden in that photo...
 

Marc W

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Mar 31, 2017
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948
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Colorado
I am ignoring it! Completely burned out on it. In fairness, I have flown it 5 hours without taking the cowl off so it is a useable airplane now. Even so, I am going elk hunting. At my age and physical condition, I am not much threat to the elk but it will get me away from the airplane for a while. Maybe when I come back I will be refreshed, inspired, and ready to tackle the next round of fixes to the airplane.
 

Kyle Boatright

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Marietta, GA
Here's a picture of the crack in the weld on the left side. The right side is cracked too, but the crack is smaller.

Also you can see the gusset Van's provides to (hopefully) prevent future cracks. It is set in place on the right side gear socket.
 

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