Reregistering an RAA aircraft

[aro]

9 hours ago, skippydiesel said:

So not the C172 listed in your bio?

Don't believe everything you read!

 

9 hours ago, skippydiesel said:

My last aircraft had a 30 knot stall speed, I could still manage to control engine speed (5200-5500 rpm) with attitude and climb out at 1000  +ft /minute.  I think most pilots are trained to adjust power/ attitude at around 500 ft (assuming no additional risk factors) Dont know your experince/training however you should know that best angle of climb (VX)  creates its own risks that must be measured against best rate of climb (VY).

People would rarely use best angle, but when you really need it you don't want to be worrying about your engine.

 

I think many Rotax powered aircraft with cruise over 100 knots or so have trouble meeting the 5200 rpm minimum at their true best angle/best rate speeds. I know e.g. the RV-12 recommended below 5200, despite Rotax recommendations. They now use the injected engine, which is a lot more flexible.

 

9 hours ago, skippydiesel said:

If you are consistently operating your engine below optimum (min 5200 rpm) there is an elevated risk of premature failure.

Evidence? If you operate WOT below 5200 there is a higher risk of detonation and sudden failure, other than that I haven't seen any credible claims.

[skippydiesel]

9 hours ago, BrendAn said:

Did you have a hard landing in that aircraft. I remember you had it for sale but needed repairs to undercarriage. ?.

 

Addressing me?

Yes I crashed my Zephyr on landing on a very dodgy farm strip  - now about 5 years ago.

I am still ashamed of the poor decisions I made  and the damage caused to a truly astonishing little aircraft.

The Zephyr has been put back into the air, by her new owner.😈

[skippydiesel]

4 hours ago, pmccarthy said:

Ok here’s a related question to the above. In my Vixxen I have taken to flying about at 4000 rpm and looking at the details below when I go for a jolly. This gives me 60 to  70 knots , vs  27 knot stall speed. I don’t think the engine is overstressed, fuel consumption is way down. Of course, cross country is 5200 to  5500 rpm, but I am doing much more slow flying at present.  Am I risking damage to the engine?

In general the greatest load/demand on your engine is from start of Ground Run to top of Climb Out.

The ideal rpm setting to address this demand, will be one that is past peak torque (in round figures  - minimum 5200 RPM for Rotax 9's).

Torque is a measure of the engines ability to do work, usually illustrated as a curve (see below).

If your engine is operating ahead of peak torque, any reduction in rpm caused by additional load, will be accommodated by an increase in torque & no additional stress on the engine. 

Few pilots can maintain a constant load on their engine, in other than perfectly smooth flying conditions, so fluctuations in load are the norm.

Operating at or below peak torque is likly to place unnecessary stress on your engine and will reduce aircraft performance when the inevitable increase in load occurs.

Rotax recomend that its 9 series engined be operated  in the range of 5200-5800 rpm for TO (minimum 5200 rpm).

 

"In my Vixxen I have taken to flying about at 4000 rpm and looking at the details below when I go for a jolly"

I would call this "loitering" - Your engine speed is perfectly acceptable in this flight condition, as long as a altitude can be easily maintained and you put "power on" to climb.

"This gives me 60 to  70 knots , vs  27 knot stall speed"

Engine setting , in this case, has  little to do with stall speed other than you need to be aware that you have reduced your margin of safety above stall.

"Am I risking damage to the engine?"

No! I would council extra vigilance not to attempt to climb(load the engine) your aircraft while loitering.😈

 

[spacesailor]

After. Reading the list of " allowed " maintenance items , it leaves me out !.

So no good my getting a L1 endorsement, as I have to do " both " magneto points & valve jap adjustments periodically. ( I also do the spark plugs gap , ( oil fogging the bores too ) ).

spacesailor

[skippydiesel]

1 hour ago, aro said:

 

 

People would rarely use best angle, but when you really need it you don't want to be worrying about your engine.

True!

 

I think many Rotax powered aircraft with cruise over 100 knots or so have trouble meeting the 5200 rpm minimum at their true best angle/best rate speeds. I know e.g. the RV-12 recommended below 5200, despite Rotax recommendations. They now use the injected engine, which is a lot more flexible.

Sorry! This is nonsense. My last aircraft would max out at 120 knots at 500 ft ASL. My current 150 knots - both Rotax 912 ULS engines. In both cases I can maintain Climb-Out above 5200 rpm just by adjusting attitude/angle of attack.

As for RV-12, I know almost nothing of the iS engines,  maybe they have a diffrent torque curve to the ULS. Whatever the reasoning I would go with the engine manufacturers recommendations, before the airframe.

 

"Evidence? If you operate WOT below 5200 there is a higher risk of detonation and sudden failure, other than that I haven't seen any credible claims."

You are confusing yourself. This is not about operating below 5200 rpm, it's about loading your engine when operating at/ below peak torque.

The poor analogy is - when cruising down the freeway, in your car, you can be in 5/6th gear and well below the engines peak torque. All good until you kit a gradient (additional load). Stay in the high gear, will likly see your speed decline and the sound of protest from your engine - keep this up and you will shorten the engines service life. The answer is to change down a gear (or two) to allow the engine to increase rpm to above peak torque thereby facilitating its ability to address the increased load (gradient) possibly even maintain cruise speed. 

You don't have an inflight adjustable gearbox, so the prudent pilot (fixed pitch prop) will cruise at or slightly above peak torque, so  the engine will have that reserve of torque to be able to address the inevitable small angle of attack changes that occur.😈

 

[Moneybox]

I knew I saw this somewhere....

 

RAAus Technical Manual

11.2.3 ISSUE AND RETENTION OF MAINTENANCE AUTHORITIES 

 

LEVEL ONE (L1) Maintenance Authority Pilot Certificate holders (non-student) may be issued with an L1 Maintenance Authority following successful completion of the RAAus training and assessment available through the L1 Maintainer Training and Assessment Site within the RAAus website. A membership lapse, of more than 2 years will require the re-validation of the maintenance authority by undertaking the course again. 

[BrendAn]

6 hours ago, skippydiesel said:

Addressing me?

Yes I crashed my Zephyr on landing on a very dodgy farm strip  - now about 5 years ago.

I am still ashamed of the poor decisions I made  and the damage caused to a truly astonishing little aircraft.

The Zephyr has been put back into the air, by her new owner.😈

Nothing to be ashamed of at all.

I never read what the cause of the incident was.  I watched a utube the other day on a new single seat atec. Beautiful looking AC. Almost all composite construction but they have stuck with the wood mainspar. I think that is a testament to wood.

 

[BrendAn]

15 minutes ago, Moneybox said:

I knew I saw this somewhere....

 

RAAus Technical Manual

11.2.3 ISSUE AND RETENTION OF MAINTENANCE AUTHORITIES 

 

LEVEL ONE (L1) Maintenance Authority Pilot Certificate holders (non-student) may be issued with an L1 Maintenance Authority following successful completion of the RAAus training and assessment available through the L1 Maintainer Training and Assessment Site within the RAAus website. A membership lapse, of more than 2 years will require the re-validation of the maintenance authority by undertaking the course again. 

It's pretty easy to find.  I did it anyway and it is listed on my profile.

Ra people know. I talk to the tech people and Nicola  quite often. 

I may not have RPC yet. But I have owned  a few aircraft.

[skippydiesel]

24 minutes ago, BrendAn said:

Nothing to be ashamed of at all.

I never read what the cause of the incident was.  I watched a utube the other day on a new single seat atec. Beautiful looking AC. Almost all composite construction but they have stuck with the wood mainspar. I think that is a testament to wood.

 

Thank you for your kind words.

I will always be ashamed of the series of poor decisions I made on the day in question ,coupled with the damage done to such a nice aircraft.

 

If you are referring to ATEC Solo - it's been around for quite a few years now; https://www.atecaircraft.eu/en/planes/atec-212-solo.

 

I am told(?) that wood has an almost infinite fatigue life - what's not to like?😈

 

Performance (ROTAX 912, 100 HP)

Cruising speed VC	260 km/h / 140 kt
Never exceed speed VNE	310 km/h / 167 kt
Stall speed (flaps extended) VS0	50 km/h / 27 kt
Stall speed (flaps retracted) VS1	70 km/h / 38 kt
Max. horizontal speed VH	290 km/h / 157 kt
Rate of climb	8,5 m/s / 1680 FPM
G-load limit	+6 / -4
Flight range	900 km
Fuel consumption (140/180 km/h)	12 L/h

Edited Tuesday at 05:52 AM by skippydiesel

[Moneybox]

10 minutes ago, skippydiesel said:

Thank you for your kind words.

I will always be ashamed of the series of poor decisions I made on the day in question ,coupled with the damage done to such a nice aircraft.

 

If you are referring to ATEC Solo - it's been around for quite a few years now; https://www.atecaircraft.eu/en/planes/atec-212-solo.

 

I am told(?) that wood has an almost infinite fatigue life - what's not to like?😈

 

Performance (ROTAX 912, 100 HP)

Cruising speed VC	260 km/h / 140 kt
Never exceed speed VNE	310 km/h / 167 kt
Stall speed (flaps extended) VS0	50 km/h / 27 kt
Stall speed (flaps retracted) VS1	70 km/h / 38 kt
Max. horizontal speed VH	290 km/h / 157 kt
Rate of climb	8,5 m/s / 1680 FPM
G-load limit	+6 / -4
Flight range	900 km
Fuel consumption (140/180 km/h)	12 L/h

Can it actually take a pilot as well as fuel?

 

Min. empty weight (Rotax 582, central fuel tank)	200 kg
Max. take-off weight	300 kg
Fuel capacity (central tank/wingtanks)	1x 50 L / 2 x 35 L

[BrendAn]

16 minutes ago, skippydiesel said:

Thank you for your kind words.

I will always be ashamed of the series of poor decisions I made on the day in question ,coupled with the damage done to such a nice aircraft.

 

If you are referring to ATEC Solo - it's been around for quite a few years now; https://www.atecaircraft.eu/en/planes/atec-212-solo.

 

I am told(?) that wood has an almost infinite fatigue life - what's not to like?😈

 

Performance (ROTAX 912, 100 HP)

Cruising speed VC	260 km/h / 140 kt
Never exceed speed VNE	310 km/h / 167 kt
Stall speed (flaps extended) VS0	50 km/h / 27 kt
Stall speed (flaps retracted) VS1	70 km/h / 38 kt
Max. horizontal speed VH	290 km/h / 157 kt
Rate of climb	8,5 m/s / 1680 FPM
G-load limit	+6 / -4
Flight range	900 km
Fuel consumption (140/180 km/h)	12 L/h

Yes it was on the experimental channel. Might have been an old episode.  

Edited Tuesday at 06:08 AM by BrendAn

[skippydiesel]

16 minutes ago, BrendAn said:

Yes it was on the experimental channel. Might have been an old episode.  

It would be great to have one in Australia - one day !😈

 

23 minutes ago, Moneybox said:

Can it actually take a pilot as well as fuel?

 

Min. empty weight (Rotax 582, central fuel tank)	200 kg
Max. take-off weight	300 kg
Fuel capacity (central tank/wingtanks)	1x 50 L / 2 x 35 L

That looks to be a miss type - I will enquire.😈

[BrendAn]

Just now, skippydiesel said:

It would be great to have one in Australia - one day !😈

 

That looks to be a miss type - I will enquire.😈

A bit slick for me but very nice.

[skippydiesel]

1 hour ago, BrendAn said:

A bit slick for me but very nice.

And with a wonderfully low stall - makes for safety and the ability to loiter at low speed for whatever?

 

😈

[Thruster88]

1 hour ago, BrendAn said:

Yes it was on the experimental channel. Might have been an old episode.  

I watched that episode a few days ago with the Atec solo. What a beautiful aircraft. I was mildly interested until the kit price was mentioned in US$. A lot lot more than I paid for a beautiful RV6a which I didn't have to build. Much more performance (and fuel consumption) in the RV and two seats.

[BrendAn]

5 minutes ago, Thruster88 said:

I watched that episode a few days ago with the Atec solo. What a beautiful aircraft. I was mildly interested until the kit price was mentioned in US$. A lot lot more than I paid for a beautiful RV6a which I didn't have to build. Much more performance (and fuel consumption) in the RV and two seats.

The RVs are nice. When we lived in Albany some blokes out at the airport almost had a production line of rv aircraft. I think they built 4 kits .

[skippydiesel]

The choice of aircraft is a very personal one. I too love the look  of RV's 3,4 & 8  - do you think there might be a trend?

 

It seems to me that the main advantage in an RV type aircraft, is that it is comparatively easy to build, to a known standard, from a multi part kit, simply because its metal. Metal has the advantage of being able to be pre shaped & drilled ready for assembly & delivered in a "flat pack".

 

Composite  aircraft can not easily be supplied as a small component kit. Homebuilt composite aircraft are usually delivered in an advanced stage of completion ( large modules) - this adds greatly to purchase cost BUT significantly reduces completion time and often results in a more aerodynamic / efficient airframe.

 

You gets what you pay for;

• Metal likly to be lower purchase cost and higher operating
• Composite higher purchase cost and lower operating

Many pilots favour high engine power - I would suggest that with the possible exception of aerobatics (don't know much about this activity), noise and bragging rights there is little if any experiential advantage in such a choice. Time & time again it has been demonstrated that a suitable airframe can be powered by a Rotax 100 hp and deliver close to RV speed & payload, at a fraction of the operating cost of the larger aircraft - what's not to like?😈

 

[aro]

22 hours ago, skippydiesel said:

Sorry! This is nonsense. My last aircraft would max out at 120 knots at 500 ft ASL. My current 150 knots - both Rotax 912 ULS engines. In both cases I can maintain Climb-Out above 5200 rpm just by adjusting attitude/angle of attack.

Maintaining rpm above 5200 by adjusting attitude/angle of attack is not climbing at best angle or best rate airspeed.

 

Faeta best rate seems to be 59 knots (the POH isn't completely clear). 5200 rpm at 59 knots and 120 knots at 5500 is double the speed for only a 6% increase in rpm. Pretty good, if true.

[turboplanner]

On 03/03/2025 at 3:54 PM, spacesailor said:

RC , I have a local field at the end of the road ,

and I could ( in theory ) register it as a " full scale flying model " .

Just needs an electric motor . Servos & a big battery .

spacesailor

LOL

MAAA controls are stricter than RA

[skippydiesel]

1 hour ago, aro said:

Maintaining rpm above 5200 by adjusting attitude/angle of attack is not climbing at best angle or best rate airspeed.

 

Faeta best rate seems to be 59 knots (the POH isn't completely clear). 5200 rpm at 59 knots and 120 knots at 5500 is double the speed for only a 6% increase in rpm. Pretty good, if true.

Dont really know what you are getting at.

 

Flying small aircraft is a dynamic activity ie the PIC must be able /willing to respond appropriately to whatever the conditions are (including aircraft performance/indications). If you see that your climb attitude (at WOT) is such that the engine is delivering below 5200 rpm,  you should be lowering the nose of the aircraft (subject to terrain/obstacle clearance) so that it can increase air speed and the rpm can climb to above 5200 - Simple!

 

There are also other factors at play with a high nose attitude;

• It is often indicative of reduced air flow through the heat exchange systems and with the high engine load extra heat is being generated - lower the nose for better airflow/cooling.
• A sudden engine failure, at high angle of attack, low air speed/residual energy,  will place additional demands on the PIC for recovery - lower the nose for increased airspeed/safety.
• Forward vision may be reduced/ flying blind - for improved forward scan lower the nose.

If this is not meeting your fixation needs ("not climbing at best angle or best rate airspeed") sorry.

 

If you persist in loading your engine, such that it is operating below max torque, you will, without any doubt, shorten its service life - your choice.😈

[3rd harmonic]

On 04/03/2025 at 9:26 AM, skippydiesel said:

In general the greatest load/demand on your engine is from start of Ground Run to top of Climb Out.

The ideal rpm setting to address this demand, will be one that is past peak torque (in round figures  - minimum 5200 RPM for Rotax 9's).

Torque is a measure of the engines ability to do work, usually illustrated as a curve (see below).

If your engine is operating ahead of peak torque, any reduction in rpm caused by additional load, will be accommodated by an increase in torque & no additional stress on the engine. 

Few pilots can maintain a constant load on their engine, in other than perfectly smooth flying conditions, so fluctuations in load are the norm.

Operating at or below peak torque is likly to place unnecessary stress on your engine and will reduce aircraft performance when the inevitable increase in load occurs.

Rotax recomend that its 9 series engined be operated  in the range of 5200-5800 rpm for TO (minimum 5200 rpm).

 

 

 

If you follow the EDGE PERFORMANCE FB feed, he often puts up VERY interesting dyno graphs of the engines he's produced or overhauled.

These are ACTUAL measured results, not theoretical speculation.

This one is particularly instructive, for the 912ULS the TORQUE curve is in reality pretty much flat above 4700RPM, HP increases are really due to increasing RPM.

Over proping the engine with too coarse a pitch, will tend to 'slug' the engine, much like changing into a higher gear on a (manual) car at too lower a speed. It definitely not going to cause any damage because the engine can't do any more than the available torque at that rpm, but the horsepower developed will be down on what would otherwise be possible.

I experienced this directly in the VH Sports-star with a CS prop, on one circuit when i forgot to set the prop rpm up to max, which as i recall was 5800rpm corresponding to 'full fine' pitch.

We were still climbing away OK, but i was indeed 'slugging' the engine at about 4800rpm! Once that was pointed out, a quick flick of the dial allowed the motor to really scream at full noise and the performance change was quite noticeable...

Edited Wednesday at 01:54 AM by 3rd harmonic

[Moneybox]

7 minutes ago, 3rd harmonic said:

 

If you follow the EDGE PERFORMANCE FB feed, he often puts up VERY interesting dyno graphs of the engines he's produced or overhauled.

These are ACTUAL measured results, not theoretical speculation.

This one is particularly instructive, for the 912ULS the TORQUE curve is in reality pretty much flat above 4700RPM, HP increases are really due to increasing RPM.

Over proping the engine with too coarse a pitch, will tend to 'slug' the engine, much like changing into a higher gear on a (manual) car at too lower a speed. It definitely not going to cause any damage because the engine can't do any more than the available torque at that rpm, but the horsepower developed will be down on what would otherwise be possible.

I experienced this directly in the VH Sports-star with a CS prop, on one circuit when i forgot to set the prop rpm up to max, which as i recall was 5800rpm corresponding to 'full fine' pitch.

We were still climbing away OK, but i was indeed 'slugging' the engine at about 4800rpm! Once that was pointed out, a quick flick of the dial allowed the motor to really scream at full noise and the performance change was quite noticeable...

That's a massive improvement to both torque and HP. A standard prop with the correct pitch would be suitable across the whole rev range.

 

[3rd harmonic]

Yeah, his engines are bloody awesome! That graph I picked out compares the Edge performance 915 to a standard 912ULS. If you look elsewhere in his photos the Edge performance version of a standard 912, but injected, has a flat 130NM torque curve from 3700rpm upwards and is good for an extra 10-12hp. Because the motor breathing is so much better and the fueling is more consistent it uses a fair amount less L/hr for the same hp.

Edited Wednesday at 02:34 AM by 3rd harmonic
Typo

[Moneybox]

These sort of modifications are great for performance but eat into the reserves of structural strength. Some automotive engines can produce massive power with minor modifications to intake, exhaust, camshaft and ECU but in the end only the best survive an endurance test. The little Rotax engines are pumping out pretty good power in standard form but we all want a bit more. You just have to weigh up the risk of overstressing a very lightly built machine.

[onetrack]

Quote

HP increases are really due to increasing RPM

Yes, that's because horsepower (or kW) is a measurement of the amount of work done in a certain time. So a higher engine speed gets more done faster. But with increasing RPM comes less efficient combustion, an increase in fuel usage (actually wasted fuel), and higher wear levels, as high engine speeds DO increase engine wear rates.

 

Edited Wednesday at 04:18 AM by onetrack