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Phoenix Air Czech Republic


Martin Stepanek

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Hello dear Phoenix owners and friends!

Some of you may know me, however I would like to introduce myself - my name is Martin Stepanek (Phoenix Air Czech Republic).

And I thing that all of you know our UL/LSA-Glider U-15 Phoenix :-)

I am flying with the prototype (01/U15) and with electric version of PhoEnix (01/D14). I know, that producer should not praise its own product, but I still have to say that I enjoy every second when I am in the air with Phoenix. Phoenix Air never had easy life and beginning of year 2016 brought changes and news - again. Negative on this situation is, that due to many things to think about I can´t sleep so well - but positive is, that I have time to be here :-) Before I was active in Forum Homebuiltairplanes - mostly about electric e-Gliding. But yesterday I found this great place = for me is much better to stay in touch with you :-)

What is my idea about this thread?

1) perfect product doesn´t exists - I will be glad to know about problems you may have with your Phoenix.

2) I would like to know your opinion about our development ideas.

3) I would like to infom you what is going here in "wild east" :-)

 

And one more little thing....

My native langauge is Czech. Due to some years in Colombia I speak also Spanish, due to primary school I understand Russian and thanks to aviation I can speak English. But because I never studied English "professionally" I still have to learn a lot about English grammar. If I don´t know how to say/write something I simply use Google translator. So... sorry if will my answer look time to time like written by robot :-) (and I still don´t understand where to use correctly "the" or "an" etc....)

Best regards!

Martin

 

 

 

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One of ideas to improve existing Phoenix airplanes (yes, I mean all already produced Phoenix airplanes) is based on the results of wing strenth testing.

Theoretically we can increase wing span to 16 or 17 meters. Of course would be necessary to make Vne limitation.

For example (not calculated yet):

short winglets Vne = 120 kts

15 meters wing ext. Vne = 120 kts

16 meters wing ext. Vne = 100 kts56b3634ab1dab_U-15.16Phoenix.thumb.jpg.7

17 meters wing ext. Vne 90 kts56b363593fbec_U-15.17Phoenix.thumb.jpg.c

Just an example.... to show you that decission is - or to make 16 meters wing ext. with small limitation, or to make a 17 meters wing ext. with bigger limitation.

System of connection would stay the same.

And second question (now more about design)....

Would you prefere to have extension leading edge straight (version 15.17) or with one more bending (vesrion 15.16)?

Suggestions and coments are welcome :-)

 

Best regards!

Martin

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Hello, Martin -

Welcome to the forum. We're delighted that you have time to participate. Many of the owners post here, and you can get a good idea of how things have developed over the years. I have U15/05, and it is doing quite well. It is a wonderful work of engineering, and it has been the most enjoyable aircraft I have ever owned. I'm sure the owners will be passing along a good bit of feedback and ideas in the coming months.

Regarding your question about longer wingtips, I think there might be some interest if there were a large enough improvement in performance to justify the cost and Vne penalty. My advice would to create the greatest possible improvement in L/D rather than just a small, incremental change. That way you would have a choice between using the 15m tips for more casual local soaring and the 17m for more ambitious trips where you are pushing your skills. I rarely need to go above 90kts anyway, so that doesn't seem to be a problem.

By the way, make sure you turn on the email notification function of this message board so you be made aware of new postings as they occur. I hope you come and post frequently to let us know what you are thinking and how we can help.

Ed

 

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Thank you Ed,

I have the same feeling - to improve L/D even if some speed limitation will be necessary.

They are two areas on the Phoenix we are actually looking to.

Already mentionned idea of longer wing extensions and some design modification on engine cowling :-)

My friend - Mr. Potmesil from HPH (http://www.hph.cz/index.php?lang=en) offered me help in case we will need CNC to make prototype moulds - that could really help.

Best regards!

Martin

.

 

  

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Martin:

Welcome to this forum.

I am eagerly awaiting the delivery of my Phoenix, which is currently in Melbourne getting its Dynon Skyview system installed.  I haven't flown it yet, but here is some preliminary feedback based on my research on the plane and my discussions with Jim Lee:

1.  I would install LEMO headphone jacks as the default standard so that pilots can power their ANR headsets from the aircraft power.  Pilots that have standard headsets can easily purchase a converter cable for ~$50.

2.  From looking at the POH, it appears that the ballistic recovery chute handle is located directly in front of the left seat.  How accessible is this to the passenger in the event that the pilot is incapacitated?  My recollection is that in other aircraft (like the Cirrus and Flight Design CT), the handle is located in the center console, so it is easily accessible from either seat.

As far as your suggestion about increasing the wingspan, I am ambivalent as long as you can still use the existing 15M extensions with a 120k VNE.  I plan on using my Phoenix at least 50% of the time as a power airplane to explore the Caribbean.  With a 30:1 L/D, if I fly at 10K ft, I am within final glide of an airport throughout the Bahamas, Virgin Islands, and beyond.  Increasing the L/D is really unnecessary for this use.  Reducing the cruise speed / VNE would definitely be undesirable.

If I am using the plane for soaring, increasing the L/D would be nice and a VNE reduction would not necessarily be a problem, in my opinion.

My biggest suggestion on improving the Phoenix is to focus your efforts on our production capacity.  I have had my aircraft on order for almost two years.  I'm sure you could easily sell 2 or 3 times your current production if the lead time was more reasonable, particularly if you marketed the aircraft in the US as an alternative to LSA aircraft for pilots who lost their medicals and don't want to be subjected to LSA operating limitations (altitude and night flying) or for use over hostile terrain where a 30:1 glide ratio gives you a lot of options if your engine quits.

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Thank you for your comment Mike,

you are right – we are very slow in serial production…

When U-15 prototype has been flown in 2009 I had a dream to go to 1 plane / month and after to try to increase production to 2 planes / month. The best year was 2012, when we approached to planned 1 plane / month. Unfortunately fuel tank issue in 2013 (or we can call it “ethanol issue”) made a big change in my plans. Well… life is life. Then came idea to use production capacity of Schempp Hirth Czech Republic (SHVL) – company we were cooperating with. Unfortunately new owner of SHVL practically destroyed the company. Result? Instead of higher production we had to look for a new lamination workshop. Actually we are finishing work on new lamination place. It will be not so big and in old factory, but I like the place a lot. Historically is in place where composite production of gliders in Czech Republic started (https://mapy.cz/s/rW4x).

I didn´t expected that our name Phoenix will predict that many “rising from the ashes”...

 

About LEMO – I have to check that. Actually we use standard headphone jacks but if I know this request before final assembly I think we can install LEMO connectors here.

 

Handle for rescue system.

Well… this depend again on request. You are right that standard position is in the front of pilot. They are two reasons why:

  1. when you want to deploy RS, you need to react fast and the handle movement is not that short as you may expect (if I remember well is around 200 mm). I don´t know what hand pilot will use so we installed this handle symmetrically and in the front of responsible person – pilot.

  2. Co-pilot is not always experienced and I would like to precede situation when co-pilot starts RS accidentally.

However, I agree that in case pilot is incapacitated is more difficult for co-pilot to grab the handle and deploy system. Exactly in the center is throttle and feathering prop handle, but technically is possible to move RS a bit more right to be easily accessible by co-pilot. On some planes I saw position of RS handle in the center, but between pilots, or above heads – sorry, that is far away too dangerous.

 

Thank you for your comments about longer wing extensions dear friend. Exploring Carribean with Phoenix sounds like a dream – please try to make some videos :-)

Best regards!

Martin

 

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Hello dear friend,

"ethanol issue" caused change of technology of fuel tank protection. Our technical supervisor (company Vanessa Air) recommended us to use system succesfully tested on more than 180 airplanes VL-3 (http://www.jmbaircraft.com/). This planes are operating mostly in EU = they are normally using MOGAS (Unleaded 95) and this fuel can contain up to 10% of ethanol. But! True is that we were not alone - also other producers reported problems with ethanol so in EU is slowly increasing net of fuel stations able to offer non-ethanol fuel. So I personally prefer to use non-ethanol fuel if is possible. When I was in US I noticed that is already not that difficult to buy non-ethanol fuel or AVGAS.

I don´t know actual prices in US but for your info this is actual situation in CR:

AVGAS L100 = 48 CZK / lit = approx 2 USD / lit

Natural 95 (MOGAS with ethanol) starts from 24 CZK / lit = 1 USD / lit

With AVGAS is one more problem - availability. Most of small airfields where we are flying with UL (your LSA) are without possibility of refueling. If there is possibility to refuel, than is MOGAS.

And one more argument to use non-ethanol fuel if available. For example in UK (but not only in UK) is LAA recommending to use less than 5% of ethanol if Rotax 4 stroke engine is installed:

This aircraft/engine (Rotax 4 stroke engine) has been checked in accordance with the procedures in TL 2.26 issue _ and may be run on unleaded petrol to BS EN 228, 95 RON (MIN) containing no more than 5% ethanol in accordance with the operating procedures and special operating limitations in TL2.26’

In fact it means to use non-ethanol fuel because in MOGAS can be up to 10% of ethanol and in future this percentage will probably increase...

Best regards!

Martin

 

 

 

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Hello Martin! Welcome! I would love to have 17m extensions, and 90kts Vne is fine in that case. Bent or straight is okay. I'm sure you will maintain the good looks.  

 

My ship 15/23 is doing fine. A wonderful ship. I agree that we need many more in the USA. There seems to be a great demand.

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  • 2 weeks later...

Hi martin

I have just purchased my Phoenix and I too would really like to see extensions that would bring the span to 17meters developed.

90 kt cruising speed is fine with me.

george feldman n33gf

 

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  • 1 month later...

Hello dear friends!

This time is my information not about TMG, but I am very glad that work of my friends from Czech Aeronautical University has been finally succesful :-)

Project name is UL-39 Albi.

More photos here...

https://www.zonerama.com/JaFR1/Album/1293931

 

Some videos here...

 

http://www.gonzoaviation.com/clanok/uhlikovy-albik

 

Best regards!

Martin

 

 

 

UL39.jpg

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Hello Martin! I am pleased to see you posting here. After all, the designer is the most likely person to have good ideas for improving his designs!

1) I would prefer 17m tips, even with only a 90 knot Vne. A smaller change in performance would not be worth the expense, and my hangar width means even the 15 meter tips must be removed. I would still use the 15m tips for traveling in "airplane mode", for safety reasons as several pilots have stated, for casual soaring the trip.

2) Would the current 15 meter wing benefit from zig-zag turbulator strips on the bottom of the wing? Zig-zag tape is cheap, and easy to install, but you must know where to put it.

3) The lower cowling looks like it produces quite a bit of drag, compared to a "smoother" design that closed the cooling intake with a streamlined cover. Also, a fairing for the exhaust pipe seems worthwhile. I'm sure you have thought about these changes and worried about the cost and complexity. Perhaps a more streamlined lower cowling could be offered as a an option for new gliders, and as a retrofit for already delivered gliders.

4) Another place I can see for improvement is the junction of the fuselage and landing gear legs. I don't know if that area has significant drag, but with the gap just above the gear leg at the fuselage, and no fillet to fair the gear leg to the body, it looks like it might be worth improving the airflow in that area.

5) Air comes into the cockpit from the spoiler and flap slots, and also from the seat belt holes in the seats. I think this air leaks in from the wing. Perhaps the sealing of the control surfaces or the wing root should be improved? This might be easy for the owner to add, if he knew where the sealing would be the most effective.

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Thank you - good ideas dear friend!

From calculations seems that 17 meters wing ext. modification will improve 3 points on L/D = I am very interested to produce them :-)    

I will try to find out if zig-zag would improve characteristics and optimal position.

I fully agree that lower covling need some modifications. Jim asked me for one spare cowling to improve it, but I understand he had no time to work on it.

At least would be good to make air intake more streamlined when is closed...

Junction between fuselage and landing gear... well that is a challenge. Landing gear is flexible so would be necessary to use something "soft". Pls. have you on your mind some solution? (drawing, photo from other airplane...).

Seal the control lines? Well... maybe, but definitelly will be a challenge to do it without to add "resistence" in control lines forces...

 

I would like to start with zig-zag tape, second goal is cowling re-design and paralelly 17 meters wing ext :-)

Than you for your comments!

Best regards!

Martin

 

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8 hours ago, Martin Stepanek said:

 Landing gear is flexible so would be necessary to use something "soft". Pls. have you on your mind some solution? (drawing, photo from other airplane...).

Seal the control lines? Well... maybe, but definitelly will be a challenge to do it without to add "resistence" in control lines forces...

I would like to start with zig-zag tape, second goal is cowling re-design and paralelly 17 meters wing ext :-)

Landing gear: my only idea is a hollow rubber fillet that is glued to the fuselage. The fillet would have the proper shape in flight, but would deform when the glider is sitting on the ground. I think some airplanes have that kind of fillet. An estimate of the performance improvement is needed to know how if it is worth pursuing the idea.

Sealing the root: This is done by Schleicher with rubber bellows on the push rods. I have done it on a Standard Cirrus and a Ka-6e with very light weight coated (air tight) fabric. It is formed into a cone shape around the push rod, with the "point" end glued to the pushrod, and the base end glued to the root. The automatic hookups might make this difficult to retrofit, but the method (or a bellows) might be easily added during manufacturing. Sealing would also make the glider more comfortable during cold weather, especially duringwave flights.

If I can help with testing zig-zag tape, I would be happy to do so; for example, Ed Walker lives less than 2 hours away by air, so he and I could easily get together to do comparison flights.

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3 hours ago, mikeschumann said:

The #1 priority needs to be increasing the aircraft production rate. 

I agree completely with Mike. As much as I would like to have increased performance, I do not want that effort to delay any production rate improvements. Better to have more owners flying than a better L/D!

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Dear friends,

development (improvement) has to go paralelly with production.

No improvement and develompent = death company (sooner or later, but for sure).

I would love to increase producton, but without investment is simply not possible...

However I can ensure you that practically all improvement work we discused above will be done externally :-)

Best regards!

Martin

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Hello martin

I see that the electric version have retractable gear,is this a posible option on the hks version also? what glideratio did you manage to get on the electric version?

Greetings from Norway

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Hello to Norway!

Sorry, D-14 electric Phoenix is existing only as one prototype.

We made this airplane for NASA/CAFE GFC (2011) and now we use it as a platform for electric propulsion tests.

Retractible gear is not an option for U-15 Phoenix. Phoenix is suposed to be operated on all airfield and airport surfaces and retractible gear is more fragile (or weight increasing if is constructed for "heavy duty" service). Also eventual repair/replacement is much more complicated in case of retractible version. Actual system is designed for easy replacement (in case off...) :-)

And finally - sorry but HKS is not an option anymore.

Rotax provides very good service and world wide guarantee. In case of Norway also Jabiru engine is good option thanks to very good representative Jabiru Scandinavia.

HKS would may bring more aerodynamic cowling, but two cylinder configuration is more vibrating at RPM below 4 000.

In case you would like to use Phoenix like "self lunch glider" (means not for travelling) than electric propulsion really can be a interesting, aerodynamic and unique option :-)

Actually is no problem to reach endurance of 2 hours + reserve.

Best regards!

Martin

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Tricycle gear Phoenix? :-)

Not yet.... this is just a mock-up made for e-Flight EXPO on AERO Friedrichshafen 2016.

And.... yes, I know that position of main gear should be more backward :-)

 

By the way...

This nice aerodynamic nose is unfortunetally only available for electric version.

Electric version has MTOW also 600 kg = endurance 4 hours (270-300 miles). Usefull load 180 kg for crew ("fuel" weight is included in planned 330 lb battery pack).

Power for takeoff - 50 kW (optionally possible up to 80 kW).

Recharge time? Tesla SC would make it in 20 minutes (120kW) :-)

But realistic 20 kW (40 kW) charger could recharge battery in 2 hours (1 hour). 

I am wondering who will make a first electric glider aero-tow :-)

My personal comment - I would still prefer to have electric taildragger configuration of landing gear, that beautifull nose and folding prop - that would be definitelly my favorite.

Best regards!

Martin3g Phoenix.jpg3g Phoenix 2.jpg 

 

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Tricycle gear would definitely expand the Phoenix market by making the aircraft more suitable for pilots and partnerships with limited or no tailwheel experience.  However, you don't need more orders.  You need more production!

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  • 2 weeks later...

Well... I am not that sure...

New lamination workshop finally started production of big parts and I want to be prepared for production increase :-)

Best regards!

Martin

 

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  • 4 weeks later...

Now that I've had a month or so of experience with my Phoenix, I would like to share a problem that I have been having with fuel leaking out of the fuel tank vents at the end of the main wing sections.  I have noticed fuel leaking from both vents on a regular basis, particularly when the tanks are full and the airplane is not on level ground.

I was wondering if the problem couldn't be easily solved by eliminating the existing fuel tank vents and replacing them with small vents that are part of the fuel tank caps?

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On 6/2/2016 at 7:18 PM, mikeschumann said:

I have noticed fuel leaking from both vents on a regular basis, particularly when the tanks are full and the airplane is not on level ground

Yours is a common experience. The simplest action is filling the tanks to no more than about 3" from the top of fueling opening, which leaves about 2 gallons of "empty space" in each tank. Another action is flying carefully with the yaw string centered, so neither tank is higher than it's wing tip.

I haven't actually seen mine leak while sitting on the ground. Perhaps that is caused by full (or nearly full) tanks that heat up, expanding the fuel (and any vapor in the tank) and pushing it out the vent.

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I would like to see an option for a right seat PIC, some like to have stick in right hand! What is the VNE in Europa if I may ask. Do you have an outside temp limitation like some others?

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