Bachem Natter

[Erfolg]

Martin, I am not sure I would necessarily agree with you. It bears more than a little in common with the original Lockheed F104 Starfighter, that of an aircraft which just went in a straight line, quick climb to altitude, unleash its weapons on the target aircraft. No pretensions to dog fighting etc.

 

It did depend a lot on automated processes during the launch phase, just as the Stuka in the dive and climb out phase, to deskill that particular phase. It certainly would have benefited from further development, though.

[Tony Bennett]

the brits were developing their own version on the isle of wight after the war, but it got scrapped

 

[Erfolg]

It would be interesting to read and see any British efforts. From reading, I have formed the impression it was policy by the RAF to limit research into new types. Miles being one of the few to have a innovative mindset. Their ideas being the M20, Canard aircraft and of course the M52, before financial collapse. Much of Miles work was privately funded and without sanction by government departments, in some cases almost in contravention of policy.

 

There was a significant research programme post war, much based on German data and concepts, with particular emphasis on the V bomber programme and Concorde. I suspect much of the inertia into initiating work, has stemmed from the UK Government, not the industry and personnel.

Edited By Erfolg on 10/05/2011 13:42:17

[Erfolg]

Richard

 

I have now found them.

 

How did you come to find them?

[Tony Bennett]

saunders -roe sr 53 was a project they drew up in 1952,

single seater 8000lb thrust bi fuel rocket, mach 2.44.

 

they decided that it would be better to fit a small jet engine as well to enable the plane to limp home under its own steam rather than glide.

this was the sr 177. it flew in 57

 

 

 

get a copy of project cancelled by derek wood.

you will be surprised about what was on the drawing boards in the 50's, 60's and 70's.

Edited By tony bennett on 10/05/2011 14:19:13

[Tony Bennett]

anyway, sorry to drift off course.

lets get back to your build.

[PatMc]

The 3 launchpad locations are given in Wiki.

 

If you increase the wingspan significantly but stick with the original elevons for pitch & roll then roll will probably be quite sluggish. Mixing rudder with roll would probably help. Possibly even having 2 servos on rudder, one top one bottom so that they can work in opposition to each other but in harmony with the elevons for roll & together for yaw (if required) - i.e. rudderons.

[001]

PatMc got it. Wiki. I was quite surprised that anyone had put the photos on Google Earth and also that the local authorities had not decided to destroy the pads.

 

I also tried to find a set of plans or drawings at a decent size. Without success.

[Martin Harris - Moderator]

Posted by Erfolg on 10/05/2011 12:06:08:

Martin, I am not sure I would necessarily agree with you. It bears more than a little in common with the original Lockheed F104 Starfighter, that of an aircraft which just went in a straight line, quick climb to altitude, unleash its weapons on the target aircraft. No pretensions to dog fighting etc.

 

It did depend a lot on automated processes during the launch phase, just as the Stuka in the dive and climb out phase, to deskill that particular phase. It certainly would have benefited from further development, though.

 

I can understand the concept - born out of desperation - but surely the comparison with the F104 is rather tenuous and based on their stubby wings. In comparison, the F104 looks like a Lazy Bee! Actually, I'm told it was a pretty good aircraft when used as intended and the Luftwaffe's insistence on using it as a multi-role (including ground attack) all-weather aircraft led to its "widow-maker" reputation.

 

However, as it's always been my opinion that leaving a perfectly serviceable aeroplane in flight is the province of the mentally unstable, getting into one that's designed to fire explosive bolts a couple of minutes into the flight in order to eject the pilot and leave him dangling under a glorified giant handkerchief requires an act of fanatical devotion to the cause - or complete insanity!

 

 

 

[DH 82A]

" A good part why I show my build process is to get feed back, some of it as to date on this thread. Normally I get a lot less than I hope for. In this case it is about "Blue foam Bodies", as this will be the first full body made from foam, for me. I am sure that others will have done more and have hard learnt lessons to pass on, if they can be reached. "

 

Try contacting Chris Golds, he has designed and built lots of models using blue foam.

[Erfolg]

Hi, Rex, I have corresponded with Chris Golds. It does seem that FF, that some free flight indoor modelers use blue foam bodies, yet I have obtained very little information.

Martin, the mission profile of both the F104 and Bachem had similarities as conceived. In that both were point interception aircraft. Both were designed with a high rate of climb. Both were meant to directly attack the intruding aircraft, using fire and forget weapons. Neither were intended to dog fight. Both had initially rudimentary or none in the case of the Bachem aids for locating target aircraft.

Tony, I was aware of the SR53 and 177. As you know it was a post war programme. I guess i should have stated that the reluctance to embark on development programmes by the RAF and Ministry of Defense was a war time policy. Born out of consideration as to development time, importantly resources, disruption to established weapons programmes, cost etc. It is interesting what killed the SR 177 was the USA removing the SR177 from the USA sponsored Marshall plan as applied to the UK, plus the USA Government getting behind the F104. It may also coincidental that the F 104 programme, was linked to some financial issues in Belgium with some very high ranking officials. I am being cautious so as not to libel anyone, if any tiny aspect of the detail is incorrect.

[Erfolg]

Well I have started with the Blue Foam and here is the highly detailed, carefully anotated drawing, the printed letter almost a work of art.

 

The blank

 

Sawn Blank, using cross cut hand saw

Carving using the latest Technological Techniques Lazer Knive (TTLK)

 

 

 

 

 

After shaping using Abrasive Alliminium Oxide Paper

Finished Ist stage shaping

 

 

[Tony Bennett]

wow looking gooooood.

[Simon Chaddock]

It is interesting to note that the 1951 Air Ministry specification OR301 called for a ramp launched rocket propelled interceptor firing a battery of 2" unguided rockets & capable of reaching 60,000ft in two and a half minutes and landing on skids.

A sort of cross between the Natter and the Me163.

 

After much delay (not surprising) and changes to the specification it lead to the SR53 which did fly (I saw it at Farnborough) and the bigger SR177 which did not.

 

[Erfolg]

Although I have not read, or have any understanding of the Air Ministry spec, which initiated to the Saunders Roe programme of work, I have read a number of accounts of the political and development aspects of the programme.

 

At the time of the programme, the Saunders Roe project was probably operationally viable, as jet engines were still very much in their early development stages. With hindsight, the operational live as a mixed power plant airframe would have been limited.

 

Yet from some sources the programme was doomed by the USA pushing the F104 to the Germans, which was also seen as a major customer for the SR177. It appears the USA did what was necessary on at least two fronts to secure the German order, which spelt the end for the SR177.

 

It is interesting that the Germans (with American support?) dabbled with zero distance launching, using a rocket to launch the F104 from a ramp. This was to engage Warsaw Pact aircraft, invading German airspace, as at that time it was thought that there would be little notice.

 

It is not clear to me how the F104 moved from a high level interceptor, to have a low level role, for which it was unsuited, the high level of deaths being an indicator of the aircraft's limitations in this role. I would guess that its payload increased from carrying a simple search radar system and two fire and forget missiles, to something far more comprehensive.

 

Anyway today, I have purchased the spars, leading and trailing edges for the Bachem. I have not decided yet what the detail design will be. Although the Bachem had a symmetrical section, I will build a flat bottom section, probably E205, although with probably a much rounded leading edge, to improve the stall characteristics. Yet I am tempted to use NACA 0015, as my Nobler has such good handling characteristics using it.

[Simon Chaddock]

Erflog

Maybe its just the camera angle but is that very nice looking fuselage a bit thinner than scale?

 

I had never heard of a U/C on a Natter but you were quite correct.

Note the low set tailplane on this glider version.

 

[Erfolg]

I do not think it is the camera angle.

 

I think it is relatively long, as a consequence of the rocket motor design. There seems to be a very long tailpipe, on the motor, I have not got a clue why. In the back end it was apparently pretty much empty, other than the pipe. The cross section, is just sufficient for a seated pilot, essentially sitting on the floor, rather than a proper seat, with the head almost touching the canopy.

 

The main issue with respect to a model, is the very small wing area, relative to the body.

 

The tailplane is also enormous, due I guess to the very short moment arm.

 

I am still less than convinced that my model will be viable, even with cheating, as to true scale outline. But I am pressing on.

[Erfolg]

I have now made the wing, somewhat of a compromise. I undertook a number of calculations, I concluded, whatever I did with true scale wing area, it was unlikely that I could get the overall weight low enough to fly as a RC model. The issue always came back to the Lipo and motor. Particularly if i wanted to fly other than in still air, where the glide angle may then be tolerable, that is better than 30 degrees

 

So I have stretched both the chord and wing to provide a similar look as a component, although when united with the body it may not have quite the look to the knowledgeable, but the average modeller may not notice. Just like so many Spitfires, particularly those which are successful as a club model. I have no time for Hanger Queens.

 

So this is the wing, in the making

 

 

More or less finished

 

 

Along side the body

 

 

My next concern is that there is an awful large amount of structure at the rear. Particularly the tailplane and motor. This will require the Lipo very much to the front. I have had this issue previously with flying wings, yet did in the end managed to avoid excessive motor leads. Will I be able to achieve the same here/

 

So far the wing is 6 oz.the body is 7 oz, in the case of the body there will be some hollowing out required. The hollowing will be to house the lipo, to run the cabling, place for the ESC, Rx etc. Wing area if memory and fag packet calcs indicate about 1.5 sq, ft wing area.

 

[Tom Wright 2]

Erfolg.

A very interesting project and good illustrations of working lumps of foam into a well shaped fus ,I would predict the success of this project might be highly reliant on keeping the wing loading as low as possible.

 

Will continue to follow the thread with interest ,if the model is as good as the research it should fly well. LOL.

 

Tom.

[Erfolg]

Although I have been agonising for a few days with respect the back end of the model, i was not prepared for the enoromity of the difficulties when look at in detail.

 

As I have stated previously i have stretched both span and chord of the main wing. Previously this has not been much of an issue with respect other models, modest adjustments go mostly unnoticed. Typically you find spitfires with slightly narrower bodies, or not as deep, or the nose length stretched etc.

 

In this case the tailplane area of the actual aircraft is somewhere between halve to two thirds the wing area. Making a cardboard template of the tailplane, it looked very small, compared with the wing I have made. I then set about increasing dimensions, with the aim of obtaining a better look and feel. Also recognising that the "static margin" value would look better with a bigger tailplane. The wing to tailplane ratio are probably a major part of the distinctive look of the real aircraft

 

 

For some reason you need to click on the image to obtain  the correct proportions.

 

I then looked at the fin and under-fin, which now look to small at a scale size, relative to the other elements. So i am now stretching those.

 

It does appear that the "road to hell, is paved with good intentions"

 

Anyway I am now making a fin and continuing to worry that I may have lost feel which I prize.

Edited By Erfolg on 19/05/2011 16:21:01

Edited By Erfolg on 19/05/2011 16:22:21

[Tom Wright 2]

I would definitely chicken out and go for an Aquila section.......you need the lift ! .never mind the drag ....unless of course you intend  to fly it at scale speed  .

Edited By tom wright 2 on 19/05/2011 16:59:18

Edited By tom wright 2 on 19/05/2011 17:16:27

[Erfolg]

Tom, I found in my days as as a competitor in 100s and open Barcs contests that undercambered sections are a waste of time, if you want to move. As fast as you go forward the model sinks as much. Where as sections such as Eppler (205, 386 etc) and the current MH 32 sections and all the other similar sections, allow penetration, with a good glide ratio.

 

Anyway the wing is made with E205, I can always use it for a 3D type profile model if this will not go.

 

In the mean time I will be pressing on, the finish will have to be a sprayed on emulsion/Acrylic paint to save weight.

[Tom Wright 2]

The basic Aquila is flat bottomed .the MH32 is a good all rounder with a better drag curve .

This is certainly going to be interesting ,Do you hope its going to be fast ,or will you be happy if it just tootles along ?

Sorry i had forgotten the wing is already built. .

 

You must be pretty confident its going to fly ,.....could have sneaked out and test flown it bare.!

Edited By tom wright 2 on 19/05/2011 17:33:34

[Erfolg]

Hmm, now you are asking.

 

I have noted, mainly from experience of my early IC models, that they often seem to have thickish wings, heavily cambered, quite often power is seen as some thing which is available in great abundance, to drag the model about. Apparent, by the sink rate of an IC model when throttled back, say for landing. A generalization, but generalisations often are not far from the general truth.

 

All of my electric models, other than the kits I have bought, have used glider sections, as good lift to drag ratios are the accepted norms. I particularly like E205, as even though it is thickish, the highish leading edge provides a camber line which is pretty flat. I noted that although it is good at loitering, a little down or reduced alpha ( as everyone seems to like to say) has the model traveling with a similar glide ratio.

 

I am not at all confident it will fly, although I remain hopeful, or it will find a corner, where it will die and never get built. I

 

am increasingly conscious of weight. I have found that emulsion paint diluted adds very little weight. Also fortunately the real Natters seem pretty rough, particularly the facsimile at the "Fantasy of Flight"

[Tom Wright 2]

I think the whole point about the old under cambered sections is that they are designed for low speed flight , if you try and make them go fast the LD becomes horrendous hence the excessive power requirement to attain speed.

As i suggested before moderate wing loading ,is going to be an important consideration ,but thinking about it ,roll control sensitivity could be even more important if its to twitchy it could be over and in very rapidly.

Don't think pitch should be a problem the reasonable moment arm and generous tail area should keep things damped down ok.

Don't know what you have in mind power wise but in view of the parasitic drag and high

whetted fus area a bit extra on tap could be handy.

The bets are on ,i look forward to further progress keep up the good work.