facthunter Posted July 21, 2023 Share Posted July 21, 2023 Jets DO tend to go higher as they get more efficient. Efficiency has a lot to do with the maximum temps permitted by the metallurgy and the blade efficiencies Axial flow is more critical in small sizes and expensive> Nev 1 Link to comment Share on other sites More sharing options...
440032 Posted July 21, 2023 Share Posted July 21, 2023 Backseating an L39 at 500 feet at 250 kts from Portsea to about Safety Beach, a while back. it's a friggen hoot. 3 1 1 Link to comment Share on other sites More sharing options...
Blueadventures Posted July 21, 2023 Share Posted July 21, 2023 17 minutes ago, 440032 said: Backseating an L39 at 500 feet at 250 kts from Portsea to about Safety Beach, a while back. it's a friggen hoot. A friend was in the one that collapsed one main leg while landing at Old Station a few years back, I was there and saw it and Deslie said it was interesting. Lucky no serious damage occurred to the airframe. 1 1 Link to comment Share on other sites More sharing options...
MattP Posted July 21, 2023 Share Posted July 21, 2023 I think their sales process is: Q. What's the range? A. Look, it's a jet! Q. What performance can I expect e.g. Stall speed, ceiling etc. A. Look it's a jet and you can build it to be aerobatic. Q. How much? A. Click. Ring back Shut up and take my money! Nobody is buying this for any practical reason whatsoever, and good on them! 3 1 Link to comment Share on other sites More sharing options...
Garfly Posted July 21, 2023 Author Share Posted July 21, 2023 Absolutely, it's a poor man's Vision Jet. ;- ) 2 Link to comment Share on other sites More sharing options...
facthunter Posted July 22, 2023 Share Posted July 22, 2023 How Hard jets are to fly is a well kept secret. Non bypass jets are low on thrust and aaaaaaaaaaaaaaare they thirsty??? Don't linga too long or you won't get (jet) back. Nev 1 1 Link to comment Share on other sites More sharing options...
ClintonB Posted July 22, 2023 Share Posted July 22, 2023 Does anyone know if the 2 seat will get a bigger jet or 2 of them for the increase in weight of load, and possibly more fuel? could you build a longer wing and get extra lift Nev is talking about for load and higher flying. 1 Link to comment Share on other sites More sharing options...
facthunter Posted July 22, 2023 Share Posted July 22, 2023 Doubling the size won't change the fundamentals. It's cold up there and would need pressurisation. Tiny Jet engines spin fast and aren't efficient. Costs would get out of hand to push further . It's all in very well known technology. This effort is cost effective for what it is. Nev 1 Link to comment Share on other sites More sharing options...
Garfly Posted July 22, 2023 Author Share Posted July 22, 2023 1 hour ago, ClintonB said: Does anyone know if the 2 seat will get a bigger jet or 2 of them for the increase in weight of load, and possibly more fuel? could you build a longer wing and get extra lift Nev is talking about for load and higher flying. The engine is the same apparently. The wing area is about 47% larger. Lots of info here: SubSonex JSX-2T Update: Successful AirVenture Debut and a Design Tweak – Reserve Your Two-Place Jet Kit Today! – Sonex Aircraft WWW.SONEXAIRCRAFT.COM The long-anticipated Two-Seat SubSonex JSX-2T was unveiled at a record-breaking EAA AirVenture Oshkosh 2022, providing the first opportunity for the public to see the new... I put the specs alongside each other here to compare. [Click the 'thumbnail' to see it properly.] 1 2 Link to comment Share on other sites More sharing options...
facthunter Posted July 23, 2023 Share Posted July 23, 2023 This is NOT a very FAST aeroplane It's never exceed speed is about the same as a B 727's clean stall speed. TO runway length required would also be considerable. No mention of pressurisation or deicing. The Macchi Jet trainer has a similar Performance to the Douglass DC 9 1 1 Link to comment Share on other sites More sharing options...
Garfly Posted July 23, 2023 Author Share Posted July 23, 2023 (edited) Yep. It's a homebuilt. Surely not pressurised. O2 units available if needed. As mentioned above, it cruises at around 200 Kt. Its engine weighs 20 kilos; smaller than an airliner's APU. Some interesting facts, for anyone interested, in this "Experimenter" article (from some years back, about a prototype of the single seater). https://www.sonexaircraft.com/wp-content/uploads/2018/01/EAASA_SubSonex_Sept_2016.pdf EXCERPTS: "BOB CARLTON COMES SCREAMING down the air show line at nearly 300 mph. The high pitch of the tiny PBS TJ100 jet engine, combined with the vivid canary yellow paint scheme, make the entrance of the JSX-2 SubSonex very hard to ignore ... The JSX-2 could easily be the everyman’s jet, and I was lucky enough to learn why in the most fun way possible—through firsthand experience studying and flying it. SPIRITED PERFORMANCE The density altitude is a whopping 7,000 feet at the runway. While the takeoff roll of the SubSonex is correspondingly long, that is immediately forgotten as the tiny landing gear break free from the runway surface. Even at this altitude, the JSX-2’s performance is so far removed from most aircraft in this weight class that I can’t help but smile. I quickly get back to business and retract the gear as the airspeed rapidly accelerates toward the maximum gear speed of 125 mph. The gear stows within seconds, and 500 feet AGL passes as I reduce the thrust to climb power (98 percent) and arm the engine’s automatic protection computer (more on that later). Climbing at 150 to 160 indicated, I reach maneuvering altitude after only three climbing legs around the airport’s perimeter. The altimeter now reads 9,500 feet MSL (density altitude of around 10,500 feet), but I’m only 3,000 or so feet above New Mexico’s high desert terrain. As I level off, I wonder to myself what the SubSonex’s performance must be like when operating out of Sonex’s home airport of Oshkosh, Wisconsin, in the dead of winter. I’m sure what I just experienced would seem positively anemic in comparison. MICROSTEPS TO MICROJETS Tiny jets have been around for decades. In fact, a fascinating array of them have popped up at AirVenture over the years. However, until recently, flying examples have been essentially limited to novelty air show acts and one-off aircraft originally designed with piston powerplants. The jet engines they used were mostly converted auxiliary power units (APUs) or upscaled RC model aircraft engines. While the former suffered from poor power-to-weight ratios and high fuel consumption, the latter lacked reliability and operational convenience. Additionally, with airframes initially designed without consideration of turbine power, the systems, aerodynamics, and performance limitations can easily negate any advantages that a jet engine (of any variety) might offer. Thus, the microjet that offered any real level of practicality remained elusive. Then, in 2008, a Czech company with decades of experience building military-grade APUs introduced something different, something game-changing. The PBS TJ100 turbojet engine was a modern, clean-sheet design with exceptional thrust-to-weight ratio and fuel economy. Unlike earlier microjet engines, it incorporated computerized digital control, an integrated starter/ generator, recirculating lubrication, and spark ignition. All of which contributed to ease of operation, along with reliable and predictable performance. People noticed. Soon, the TJ100 became very desirable for both small manned aircraft and drone applications. Previously built microjets that struggled with engine reliability for years quietly began to convert to PBS engines. While other applications that had been waiting for just such an engine began to move beyond imaginations and into reality Sonex Aircraft founder and legendary sport plane designer John Monnett set about designing a completely new Sonex. His design would revolve around PBS turbojet power and be optimized to take full advantage of it." Edited July 23, 2023 by Garfly 2 Link to comment Share on other sites More sharing options...
BrendAn Posted July 23, 2023 Share Posted July 23, 2023 (edited) 8 hours ago, facthunter said: This is NOT a very FAST aeroplane It's never exceed speed is about the same as a B 727's clean stall speed. TO runway length required would also be considerable. No mention of pressurisation or deicing. The Macchi Jet trainer has a similar Performance to the Douglass DC 9 its a single seat kit plane. i am pretty sure he wasn't comparing it to a commercial airliner when he purchased it. Edited July 23, 2023 by BrendAn Link to comment Share on other sites More sharing options...
BrendAn Posted July 23, 2023 Share Posted July 23, 2023 😄😄 Link to comment Share on other sites More sharing options...
johnm Posted July 23, 2023 Share Posted July 23, 2023 PBS TJ100 jet engine - google says $65 k to buy the engine - assuming US dollars by way of comparison a B737 engine cost $ 15,000,000 !?! ................ still hoping my investments will ................... 1 Link to comment Share on other sites More sharing options...
Garfly Posted July 23, 2023 Author Share Posted July 23, 2023 2 Link to comment Share on other sites More sharing options...
facthunter Posted July 24, 2023 Share Posted July 24, 2023 Brendan, I' m really only trying to be realistic about the speeds. (It's NOT THAT fast) One thing is there's no pushing of the boundaries in the technology and it should be therefore safe but the cost would make it unavailable to most of us and I'd tire of it's limited envelope in a short time. I'd use a drifter More and that's something we can all afford... I also DID expand (glowingly) on the Waco when it was posted. Jets were made out to be Oh,Ah things only the "aces of bases" fly. As I mentioned earlier.. It's a bit of a Myth, when you know the reality. There's one thing about fast. when you get lost, you are getting lost more quickly and you might need 25+ miles to slow down and that's with speedbrakes. Nev 2 1 Link to comment Share on other sites More sharing options...
Area-51 Posted July 24, 2023 Share Posted July 24, 2023 I like the dual spindle main gear; makes it more big plane impressive 3 Link to comment Share on other sites More sharing options...
facthunter Posted July 24, 2023 Share Posted July 24, 2023 Safer too. Nev 2 Link to comment Share on other sites More sharing options...
BrendAn Posted July 24, 2023 Share Posted July 24, 2023 (edited) 55 minutes ago, facthunter said: Brendan, I' m really only trying to be realistic about the speeds. (It's NOT THAT fast) One thing is there's no pushing of the boundaries in the technology and it should be therefore safe but the cost would make it unavailable to most of us and I'd tire of it's limited envelope in a short time. I'd use a drifter More and that's something we can all afford... I also DID expand (glowingly) on the Waco when it was posted. Jets were made out to be Oh,Ah things only the "aces of bases" fly. As I mentioned earlier.. It's a bit of a Myth, when you know the reality. There's one thing about fast. when you get lost, you are getting lost more quickly and you might need 25+ miles to slow down and that's with speedbrakes. Nev Great post nev. I understand what you were getting at now. Edited July 24, 2023 by BrendAn 1 Link to comment Share on other sites More sharing options...
facthunter Posted July 24, 2023 Share Posted July 24, 2023 Thanx B. Nev 1 Link to comment Share on other sites More sharing options...
BrendAn Posted July 24, 2023 Share Posted July 24, 2023 mike patey gives a good run down on his engine exploding on the way to oshkosh 2 Link to comment Share on other sites More sharing options...
Area-51 Posted July 24, 2023 Share Posted July 24, 2023 🤷🏼♂️ The american made motor exploded 🍩🙀 amazing. Glad to hear they all walked away. 1 1 Link to comment Share on other sites More sharing options...
Bosi72 Posted July 24, 2023 Share Posted July 24, 2023 5 hours ago, Area-51 said: 🤷🏼♂️ The american made motor exploded 🍩🙀 amazing. Glad to hear they all walked away. I didn't understand was this an 5 hours engine or engine close to overhaul ? Glad to hear both of them safely on the ground. Link to comment Share on other sites More sharing options...
facthunter Posted July 25, 2023 Share Posted July 25, 2023 Similar Turboprop engines are at least 10 times more reliable than piston engines. So good they have made single engined planes (so equipped) considered very safe. If you overtemp the turbine it will fail. You'd want to know the cause of this tending to be dramatic occurrence. Nev 1 Link to comment Share on other sites More sharing options...
BrendAn Posted July 25, 2023 Share Posted July 25, 2023 4 hours ago, facthunter said: Similar Turboprop engines are at least 10 times more reliable than piston engines. So good they have made single engined planes (so equipped) considered very safe. If you overtemp the turbine it will fail. You'd want to know the cause of this tending to be dramatic occurrence. Nev have you watched the video. mike patey gives a good account of what happened and he is now trying to find out what caused it. he said himself that a failure like that is unheard of in a pratt and whitney turbine. the engine was secondhand so he is thinking something happened earlier in its life. like incorrect starting procedures. i think that plane is the world speed record holder for a single prop . Link to comment Share on other sites More sharing options...
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