Kenlsa

The Jab and Bing were developed in the days that we were limited to 5k feet, so it all worked out nicely, thanks very much.  Now we have 10k feet and where you lean a LyCon carb  above 5k,  we never ventured there until lately.  It is understandable that our little planes need leaning. The few times we fly up there the Bing is OK.

BUT, we must ask ourselves "how often are we near 8 to 10K?".  Not often I bet.  The80/20 rule still applies.

I have got to say that I get a nose bleed if above 2k as I like to get some sensation of speed and look around at the ground features. This is what Rec flying is all about.

If you want to play up there often, you will have to have some capability to monitor and adjust. So a an analog or electronic indicator of 23-24 inches with associated cables/handles, and panel space to fit it all.  This adds complexity and weight. Or you could go full EFI with more complexity and even more weight.

You will do most of your flying under 5k- So keep it simple, keep it light, look outside and enjoy the ride.

Ken

All low comps are from ex valve, with evidence of lead hammered into the face. OK after a quick grind and back to flying.

Re the dark oil - induction system is ok with clean filters. No induction changes have occurred. This is not on just one plane, but occurred on 3 at similar times. Just hope it isn't one pilot taking a new plane each time and flying with he carb heat on, looking for dust storms!

Ken

Our operation runs 4 Jabs (3x170, Gen4-- 1x230 Gen2) as well as a Roko.

In the last few months the Jabs (Roko under major repair--tin work) have needed to have their heads removed due to low compression, 6 from memory.  Initially it was only the Gen4s and on inspection there was a large amount of lead in the chamber/ex valve seat. Far more than we would normally see. The engines are mid life. We have been running Gen4 since they first came out as part of a Beta test, and have never had a problem like this before.

We run flat out, with a 25 hourly every 2 weeks per aircraft, with a new motor every 2 years.

Typically the lead comes off just by touching it with a finger nail and some of the pieces are the size of a corn flake and break off to bare metal underneath. The remaining deposits only need a light scrape and it instantly powders like corn flour. No real need for a wire brush, though it does clean it up like new, almost instantly.  Previously, lead needed quite some work to remove. Not these last few months. The gen 4 also showed signs of gummy/hard deposits in the ring grooves.

Oil was filthy after 25 hours, far more than usual. To keep the rings clean we have reverted (under advisement) to Straight 100 for 25 hours and that fixed the dirty oil problem OK and colour/deposits are now back to normal.

What was going on? At least the 230 is OK, so maybe there is something with the Gen4 we said........Until yesterday.

As well as another 170 with dud compression on 1 pot, the 230 now has comps in the high 40s. This aircraft is on its second motor (first replaced due to prop strike) and mid life. It has always been high 70s/80. What you would call a keeper of an engine. It was very hard to start when we warmed it up for its 50 hourly. Cold pull thru was low as well. This is our touring plane and isn't used as much.

Cyl 2,3 and 6 were lucky to get to 48/80. the rest were at 75/80.  Heads off and inspection revealed the same problem as the Gen4. Finger nail touch method removed a lot of the lead, in large chunks and the rest was easily removed with a gentle scrape. After clean up we found some old lead deposits on top of the valve, that you just could not get off easily (just like old times!).

As stated these are training aircraft and flown every day. We have NEVER had a problem like this, so many in only a few months.

So, the committee has decided to run a trial period of MOGAS asap, with a view to completely converting the whole fleet over if it proves beneficial.

I run MOGAS in my Jab with no problems as a private owner and can't see a problem with any fleet use.

I know that many of you run MOGAS in your private planes, but I am interested if any schools are running it in their fleet? 

Has there been a bad batch of fuel?

Anybody else note the same in the last 3 months?   

I will keep you posted.

Ken

Only if you can stop that wing spinning?. No money in gyrocopters for RAAus, they would be viewed as competition.

Looks like Gyros are to be included in the US of A, LSA system

Ken

I went for old blood MM, and new with Danni to put someone new to RAAus without any GA flying experience of note

Ken

RF, there was a double decker built at Stonfield gliding club in SA about 5 years ago. Afaik, the builder moved on after a series glider prang in Europe I think. I only viewed it empty and don't know if it was ever used as such

Ken

My SP has a fuzz refuel point. I have had 2 spine ops any I find it very convenient to just lift the Jerry to waist height. No need to take any steps as well.

Ken

Best ring Bert Flood, the agent.

Ken

you are about to discover the true cost of ownership!

Ken

Further to the above, you could say that if you decide to sell after a few years you will get your money back. I can hear most of us laughing already.

Example, my perfect condition plane lost HALF its value in a few weeks, after CASA decided that my Jab motor was going to kill me. I'm sure the other jab jockeys would agree about this!

Ken

I wrote an article in Sport Pilot a number of years ago. After doing all the maths with hours,fuel etc it was probably affordable.

BUT, factor in the cost of a hangar @ 35 to 50k, plus site lease and insurance, turned out it was far cheaper to hire a club plane.

It wasn't so bad if you are at it for 20 years.

Back of pie wrapper maths---30h/year @ $180hr x 20 years =$108k hire.

Own it...30h/y @ $75hr x 20years = 45k, add 50k for reasonable plane, 45k for a hangar =$140k insurance and site lease included.

I know you may say that you will fly 100 hrs a year to reduce the fixed cost per hour, BUT most pilots I know started at 100 in their first year and tapered off rapidly to less than 20. And most quit altogether after 5 years.

If I remember correctly RAAus say we fly 30 hrs average across pilots, but that doesn't take into account students who quickly rack up the hours inflating the average.

Also factor in the lost interest on the $100k for the plane and hangar at 5% over 20 years ...WAIT for it....$170k!

All in today's rates. This will allow you 47 hr per year and you still have your $100k principal. So you are well in front.

This was explored on this site last year by members. I don't have my original article electronically any more, just the hard copy.

Ken

Marty-d, Re SAMs being able to take care of business, my days with Rapier and Redeye (became the Stinger) led me to believe that if a plane was flying at a certain height at a certain speed and we had info on its track and heading etc we should be able to to hit it, so long as we were quick enough to fire when in our envelope.

But if it was a Tuesday while a heard of zebras ran by us all was lost.

For infantry protection we had to be always ready, all the time. Bit of an ask.

I'm sure the newer stuff is better but it isn't real straight forward.

Might be a bit of a hoot to give it a go tho.

Ken

RF. The reason not to continually run with a mixed brew is that the factory will "certify" their engines to performance standards on ONE type of fuel, neat. Then they may do it for another. For example Jab have approved Avgas OR Mogas, ( no ethanol tho) but not continually mixed.

They will not do it as they have zero control over the respective properties. Imagine running an engine test with 10%, 20%, 30% etc mix of car/plane fuels, then getting down to 1% increments after that. The cost would be mind blowing.

The factory allows you to transition mix the fuel from one to another when converting.

Ken

The less people that view my flying abilities the longer I will be able to keep my certificate

Ken

Good work waraton. My gen 1 is able to use most of the CAMit stuff.

Ken

Sav1770. Enjoy your new plane and this site.

Ken

This sort of thing should go thru RAAus et al, so as to ensure broad coverage. It will also give us some feeling of security and we would be more comfortable answering your questions if sanctioned by our organisations.

Ken

Spenaroo, Gawler hire out J170s, best check the web site for cost.

Ken

Did a test on a J170 last week and only got a gravity flow of 36 lts/hr. Not enough for WOT. This was with an old fuel filter. Electric pump was 42 lts, so that is ok when on mech pump. When a new filter was used, Gravity was 40lts and elec was 46lts.

The next J170 flowed 60lts on elec. So looks like each a/c needs to rely on each of the 3 systems, Gravity, Elec, Mech somewhat differently. I suppose gravity would work in S/L flight but unless you have a full tank with a good head working for you, it may not be enough on climb out.

I know that it is all tested on the factory proof plane, but on yours? Best check the actual figures.

The jab has a lot of pipe work and 15lts (?) behind the seat and all that imparts a fair bit of friction in the system, as compared with a Sonex where the tank practically feeds directly into the carb.

Ken

Before I commit......who are you, who do you represent, and why do you want to know from us?

Ken

I was suffering with flooding problems on the Jab at idle, so attached a gauge and found 2.6 psi for the electric pump and over 5 for the engine pump. I had a spare pump anyway and pushrod and after contacting the factory I found that one was about 0.8mm ( from memory) shorter and used the shorter one on my pump and this dropped it to 4.35 psi. Problem solved.

Ken

Generally the magazine is of high quality but too many photos of GA aircraft. I would have thought that there was an abundance of rec a/c available

Ken

RF, you are overthinking all this with your multiple questions. Trust in the factory as they have signed off on their aircraft.

If you don't relax and enjoy your training you may end up with an aneurism.

Pick ANY of the common brands and enjoy!

Ken

Skippy, don't worry about it......seems that you have been nominated as the new whipping boy since they flogged Don out of the way.

Ken

The Smart Car was a crumple zone looking for a place to occur.

Ken