Justin's Raven

[justin.schoeman]

Still no flying...

I temporarily solved the fuel pressure variation issue by setting the minimum fuel to 20L (with this as a base, there is enough head to minimise pressure variations).

But still not good enough... The test pilot want 120kph (65kts) on the ground, but I only hit 60kts before the abort point (although it does still feel like it is accelerating well at this point).

Tomorrow I will redo the top end for 8.5:1 compression ratio. This will mean that I loose the ability to run on Mogas, but should give me around 5% more torque (which equates to around 10% more power on the same prop). Hopefully this will get me to 65kts before the abort point, allowing for a safe take-off decision.

I also saw an interesting post on the AirVW forum this morning, where someone claimed to have been safely running an Ivo Medium prop for the last 2 years (with Ron's approval). This opens the interesting possibility of using an in-flight adjustable prop... The ability to run 3600RPM for the take-off roll and initial climb gives an instant ~20% boost in performance - which couild make a huge difference up here. The problem is - at some point I have to decide whether to keep on with the VW, or just give up on flying it in a relatively large plane at this altitude...

[justin.schoeman]

Nothing is ever easy (or quick). Finally got everything together and tested at 8.5:1 CR.

Did some testing today. Static is up from 2950 to 3020. And if history is anything to go by, I should gain another ~50 as it breaks in. Fast taxi runs are better. RPM only drops to around 2950 as the prop un-stalls, and is back up to 3000 at 50kts. There was a nasty cross wind, so I pulled the power at 55kts - it was just getting to hard to keep it straight an wheels on the ground. This was at the same spot as I had 50kts before, so it looks to accelerate about 10% quicker.

As I was slowing down through 50kts I decided to test rotation, and eased back on the stick. It did not rotate, but popped off the runway in a level attitude I held it off for about 100m before easing it down and braking. So it may not fly, but it makes a fun ground effect glider .

Time to get the test pilot to give his opinion again...

[AndyCAP]

Woohoo!! I think that qualifies as a first flight! You must really have been grinning after that hop! Sooo close noy. Keep at it Justin!

[AndyCAP]

Hey Justin! Whats news?

[justin.schoeman]

Hey Justin! Whats news?

Don't ask... Seems no test pilot wants to fly it out of Rhino Park - runway is just too short.

Waiting for another test pilot with lots of experience on type (owns a Zenith 601 HDS with VW power plant) to come over, and give his opinion, and I will decide from there what to do...

[German]

How long is too short?

[justin.schoeman]

How long is too short?

850m... Just long enough to do a bunny hop in ground effect and stop safely - but not long enough to get up to climb speed, and still land back.

[AndyCAP]

Does make sense I suppose. One has to manage the risks of a first flight. Whats the pt involved with removing the wings and trailering her to to a longer runway. Perhaps boom or springs? Im sure you would not be too keen but I guess one must consider the guy who is taking the risk of the first (err second ) flight.

[justin.schoeman]

Does make sense I suppose. One has to manage the risks of a first flight. Whats the pt involved with removing the wings and trailering her to to a longer runway. Perhaps boom or springs? Im sure you would not be too keen but I guess one must consider the guy who is taking the risk of the first (err second ) flight.

Yeah. The problem is, I initially wanted to take it to the boom, but the test pilot said that he didn't believe in bunny hops, and Rhino would be fine...

Taking off and replacing the wings takes about an hour each time, so it is not a major headache. The problem is the 2.2m wheel base that does not fit on any trailer I have been able to find. This generally means getting innovative with planks and trusses to lift/load the thing. On average so far, it is about 4 hours to load, and the same to unload. If I have to trailer it again, I will weld a frame to fit the UC, to hopefully make it easier to load and unload...

And the biggest PT is actually finding hangarage, and the schlepp of hauling an entire workshop off to springs each day to do whatever changes the test pilot wants.

[Tortoise man]

Justin hi
I follow your built from the very start and so a lot of uther guys and girls i beleave.
I got so angry at my first test pilot that i nearly fly my plane self.
I would have killed myself .
I was lucky to get louis Van Wyk from AERO SPORT after i have done everything the first test pilot want and then told me he can not fly my plane anymore.
I have 112 hours after 4 month on my plane.
Thanks to louis and all the support i got from all the friends with the built and test flight.
Very soon Justin you would be there keep going, if it was easy every one was in the sky.
Greetings t man

[justin.schoeman]

Made some progress today. I wanted to test an alternate prop, but unfortunately the engineers did not finish the new prop spacer on time.

I did, however, get another test pilot out to do an inspection, and some fast taxi runs. He is very experienced on type (owning a VW powered 601HDS himself). I joined him in the cockpit for the taxi runs, so I could show him the instruments and systems. He wanted to taxi with the nose up, to evaluate controllability and acceleration.

Well, 350m later we were airborne. The test pilot did a few control tests, and landed back. Used mostly aerodynamic breaking, and easily stopped well before the end of Rhino Park's 850m! Repeated the exercise another two times, and declared that he was confident that the plane would fly, but would be marginal 2 up...

He also said that he would be ok to test fly the plane out of Rhino Park, rather than me having to disassemble the plane and trailer it to Springs.

Will hopefully be able to get the full test program flown in the next week, or two. I just hope that it proves to fly OK with 2 up, or I am going to have real trouble getting a conversion onto the plane...

[AndyCAP]

Sounds good Justin! I am sure you will manage to improve the performance. Firsts step is to get her flying solo. All the best!

[justin.schoeman]

I have finally got the borrowed prop mounted, and it seems amazing. Static RPM up to 3050, and unloads to 3100 at 50kts. And performance seems great. Doing bunny hops down the runway, and landing back (never mind lifting off) at the intersection (around 350m).

But I have decided to ban myself from the cockpit until I am current again... My landings were not exactly pretty - the plane is rock solid in pitch, but twitchy in roll...

Test flight next weekend if everything works out!

[Pietb]

Good Luck Justin !!

[Scotsman]

The cowling worked out well..looks good in the photo.