Hi
I having been watching the Jets scene with interest for some time and i have been wondering where the future lies.
Is the day of the big complicated 36lb thrust jet past in favour of the smaller simpler lighter Wren 54/44 type jets.
Or does the future lie somewhere in between?

What is other peoples opinion?

Mike

The future is Wren... " Tomorrows Turbine Today "..

Hmmm ..I should put a copyright on that...

I see it going both ways..bigger heavier, more complex (and multi engined).......and smaller, more compact.. There may even be a market for even smaller turbines....

Maybe we will see progress on fuel consumption, and noise footprints. Maybe we will see practical turbo fans........ Treadstone..are you taking notes?

.. Combustor efficiency and emissions are always high on the agenda in any development programme and in our case ...small micro turbines, probably the easiest to look at...it all comes down to what money you can afford to spend for what gain.

Both ways
take a look at all the other disciplines in aeromodelling and they each expand both ways
the only thing that will limit you is how much you can afford,and can you get it off and back on your runway.

regards
Brian

i see it going to mostly arf big and small
i think you will see alot more electric jets also
just my 2 cents
vinny

turbines the future will be better fuel mangement

Hi
Saying as I started this debate I thought I would put my own impressions on the record.
I think the super sized super scale jobs will still be around however I think they will be fewer in number, I also think the continuing growth in the Jet sector will be down to the smaller Jets the Wrens 54/44 size. For proof of this you only have to look at the L39/MW44 thread. It is on it 70 plus page and the poor( or maybe happy guy) who is making the L39 kits cant make enough of them.
Speaking for myself I will be looking for the smaller end of the market. Planes that fit the Super sport. The likes of a Avonds F15 or a Yellow Raptor would be as big ( and as expensive as I would go ).
My main reason is that I dont want to put all my eggs in one basket. For one big complex Jet I can have several less complex and more affordable jets.
Part of the reason for starting this thread was hopefully to show the kit makers where the future lies and hopefully see more kits coming out to meet that market.

Mike

The smaller, less expensive turbines along with the ever increasing selection of smaller airframes to put them in, is going to really increase their popularity. They will also attract more newbies. But, they will not replace the big, more elaborate (expensive) models.

more power.......

CHEAPER TURBINES!

Mike

I share your point of view , if only because we are short of sites in Scotland to fly the bigger scale type models.I am only going to build models that I can fly at my club field which has a short tarmac runway which is mostly used for takeoff, most landings are done on grass.

I have A Wren 54Mk3 and a 44. I am concentrating on suitable airframes for these turbines. Unfortunately until a lot more 44's are sold the airframes will be limited to what is curently available. I know Skymasters will not be doing anything for the 44 as the market is too small.

I am looking at the Thorpe Hawk for my next 44 project and the Grumania Eurofighter for the 54.

John

My personal opinion is that we will see a few new airframes for the 44 size as more 44's are produced into the marketplace. There is a limited market for these as they require a somewhat more elevated level of modelling expertise to work inside the smaller airframes. However; their smaller airfield ops requirements are an attractive trait.

The 66 class will see a steady market and most innovation in airframes and engines will hit the market here first as this is still the largest installed user base of engines. The larger engines and airframes are going to remain a niche market as the money to develop in this upscale arena is vastly larger than that of the 66 class. Possibly there will be a small market aggression in this class in the USA, where larger sells better, bit not worldwide.

Market expansion will only really take place if the cost to build/buy one's first turbine and airframe drops to a level commensurate with the disposable income available. At the present time and for the foreseeable future it would seem that turbine cost will stay fairly level for the engine's class. There does not appear to be any major cost cutting development on the horizon for engines that are still going to be safe and of consistent operating quality. Airframes are another matter and the recent insurgence of good quality ARF's into the marketplace has added a new dimension to the market, where a non-modeller can toss enough money at a plan to become a jet pilot to have a good airframe and engine ready to fly in a few weeks time. The issue is the person's piloting and maintenance capabilities, but that is a question for another thread.

We may see axial turbines soon, but likely just as demonstration units and not production level for at least a few years. Probably the axial does not offer any major improvement to the units we are using today other than radial size, to justify the additional expense, so possibly these may never make production levels? I am not any sort of an expert, just my own opinion. I agree with Wayne that we will probably see production turbofans in a year or two... there is a demonstrated market for these units. Probably similar market size to the turboprop market?

Just like in the computer marketplace, where we envision software and then beg and plead with hardware developers to make the power so we can develop the software... we can envision airframes that are spectacular, but no one will build a production level unit until a powerplant exists to put into it! For example a very functional smaller F-14 could be made with two very narrow diameter axial turbines, for a small field op situation with more than enough power to be ballistic...the airframe would be in a 44 size by today's standards but have MW54SS or P-80 thrust out of each engine. This is an attractive plan but presently not practical for many reasons, not the least of which is that the engines do not yet exist! This would be a one piece (swept wing) transport in a present day automobile.

Sorry to prattle on...
Len

Yep, it will all be over when the Government steps in and says you are going to have to put O/2 sensors & a Catalytic Converter on that thing. Don't laugh, it is not so far fetched as to be a real expectation of our Governing body relating to emission control.[X(] Savor the sound, because Electrics are the future.

The 44/micro sized models seem popular on the internet, but everyone I see seems to be chasing one or 2 models that they cannot buy, while a few are converting electric models for them. Plus I am only 41 and I can barely see even Bandit sized models! I have no idea why anyone would want a small jet, but that is just me. I think this is a case of the internet over amplifying a marke segment, either that or the airframe people are missing a big market!


Meanwhile several companies (Tamjet, Skymaster, BMV) are pumping out new P-120 sized ARF models it seems like every month.

I think the real question is whether someone will commit to huge production numbers and make something cheap (ie copy of a popular motor) in China that will be able to compete..looks like their first attempts to rip someone off were abortive at best.

IMHO, I have to agree with most......big, easy to see ARFs, with big power and performance at an affordable price point will dominate the real sales numbers (but may not dominate the internet scene!!)

Matt,

DITTO!!

That's it exactly!

John

I test flew a Wren 44 sized model this past weekend and while I really enjoyed flying it, it really taxed my eyeballs. I like the larger and also the more complex models. I think each have there own place.

I think Mike is right about the hobby going small and large. When you start flying scale airplanes the larger ones fly much better.

I have been concerned about being able to see the smaller airplane but I would like to be able to fly off of our club field which is too small for the larger jets. I think the size of the flying site is going to have a lot to do with the decision on what size plane.

Hal

Future of the jets? I would like to see a control system to allow us to fly our jets beyond
visual range, so we wouldn't need to make 180 degrees turns each 3 seconds before we lose
visual contact. it would be fun to see the curvature of the earth!

Aircraft engines are regulated on CO, HC, NOx and Smoke.. combustor efficiency brings with it a reduction in these, i dont think anyone will jump on us just yet but we could help ourselves make the fuel we have available on board last longer

AFTERBURNER!!!!

Lets see the realism pushed that extra step. Imagine flying your AD F16 on a slow flyby and then switching to afterburner mode and seeing that concentric coned flame shoot out the back with a sudden near deafening roaring.

Zack,

Realism for us modelers i'm afraid is carting enough fuel around to give us a decent flight time without takeoff wing loadings measured in tons per Sq inch.. and fuselages that are not one huge fuel tank...

In a jet without an afterburner the combustor is positioned, between the compressor and the turbine, simple but it's operating point is characterized by low mach numbers and high cycle pressures...still simple enough..

If more thrust is required there are two ways you can go about this..

Scale up the whole engine, however this has the penalty of lugging a bloody great engine around with you all the time..

Or..

Put an afterburner on the back of it [:@]

This is a low pressure combustion system which puts additional heat into the flow and provides a thrust boost Proportional to the square root of the temperature change...i.e you have to chuck bucketful's more fuel in.

Afterburners run at relatively low pressure conditions and hence are thermodynamically inefficient so the resultant specific fuel consumption is very poor.

Also from a technology point of view its a challenge to burn under these relatively high mach number / Low pressure conditions.

Afterburners might look and sound sexy but are for us modelers are impractical...a bit like Women

AFTERBURNERS

Anyone who has seen the Traplet DVD on the Arlhorn meeting in Germany, will know that model afterburners are already here! Ok the model demonstrating them was hand built by an enthusiast and is not publicly available. But what a demonstration to show! It is worth buying the DVD just to watch that one item.


When you think the Wren Supersport is already delivering an 800mph exhaust, the possibility of an afterburner on top that suggests the need for a mobile telephone type control feedback loop will become overwhelming. My guess is that model jet technology is developing very rapidly and there are a lot more excitements in front of us.

However as far as I am concerned, there are few parametres which will not change.

It has still got to fit in my car and workshop.

I have still got to carry it - as two (or more) man operation means more organisation and less frequent flying.

My eyes and my mind have/has still got to keep up with it. I suspect this is where the real crunch will come and that "anno domini" will force a lot of us back to "basic slow moving jets".

Skypipe of Germany has been offering their Xm-69 with full afterburner commercially for, what, four years now?

Hi
For me I would rather see more efficient turbines before we see after burners.
I have to question what the point would be of having them.
Afterburner means more thrust, which means more fuel, higher speeds, increased loading on the airframe which means stronger airframes which mean heavier airframes and the circle spirals in the wrong direction.

We can already exceed 1 to 1 power to wieght ratios so why add the complication and the increased fuel load. We already exceeding scale speed by quite a dunt.

More efficient turbines means less fuel which equals lower wing loading which means a more pleasant plane to fly.

Well it does to my thinking, I await the flack.

Mike

ps given the current circumstance our colonial cousins have with the AMA do you honestly think they will let hobbyist fly a model plane, a jet even on a telemetry link " I DONT THINK SO"