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Kyle Communications

760kg upgrade and CASA consultation

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29 minutes ago, jetjr said:

...,, but stalls with full flap at 47 KIAS.

I think you will find that it is stall speed in CAS not IAS. Generally, CAS is a higher figure than IAS. Then there is the technical issue of determining stall speed in CAS for some.

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 A slight reduction in weight would fix such a close  to OK situation. The Victa doesn't have a very large wing, either. VG's done well are another possibility

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CASA words not mine

Wouldn't VG constitute a change? Reckon owners wont have the choice to vary from builders numbers however plenty wont have full flap stalls at lower than full MTOW id have thought?

Determining accurate stall speed isn't easy.

Its been mentioned the minimum stall speed was argued to be deleted due to difficulty in testing it

 

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I’m sure CASA will rely on the published figure at the date of manufacture. They will not be bothered with arguments about VGs and the like. One knot over is a fail.

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Weight has a direct bearing on stall speeds. Plenty of planes recalculate for every landing (and the approach speeds which also relate to stall speeds)  Nev

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3 minutes ago, facthunter said:

Weight has a direct bearing on stall speeds. Plenty of planes recalculate for every landing (and the approach speeds which also relate to stall speeds)  Nev

You are not allowed to reduce the aircraft's certified MTOW to meet the 760kg, same would apply for stall speed.

The 400 odd 150,152 plus a few others will be it.  

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7 minutes ago, pmccarthy said:

I’m sure CASA will rely on the published figure at the date of manufacture. 

Certified aeroplanes are required to determine Vso in CAS however the figure may not be in the AFM/POH as I have discovered.

39 minutes ago, jetjr said:

CASA words not mine

.....

Its been mentioned the minimum stall speed was argued to be deleted due to difficulty in testing it

 

Yep, I think someone in CASA will eventually work it out.

......

Even homebuilt aircraft are supposed to determine stall speed in CAS per https://www.casa.gov.au/file/122726/download?token=NFLC3fMe

per https://www.casa.gov.au/file/152031/download?token=8ztVbEcR

so CASA thinks that the figures are available. I am sceptical.

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You wouldn't want to put a lot of loose fabric and dented planes through a test for actual stall speed demonstrated. Reducing a STRUCTURAL AUW makes everything more safe if the figures make any sense for payload remaining.  Nev

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yes however as you correctly said

"If you have a figure you stick to it. No ifs or buts.  If you aren't happy with the principle by all means talk about it. . No "I'm only a little bit over so please make an exception" situations .  Nev"

Whats the good of a rigid stall speed if aircraft don't meet it or its too hard to validate after certification

PLUS the whole overloading issue, if fuel is the main weight it may have excess stall at take off but not later.

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The Rans S21 Outbound shows the ins and outs of the new rules if they do come in.

Rotax is 1600 lb MTOW and the Titan is 1800 lb MTOW  The stall full flap with the Rotax is 38mph and the Titan is 40mph so both fit the stall criteria but the Titan fails the MTOW weight so there will be plenty that work and plenty that dont but it does mean more variety available to fly.

 

 

Rans S21 Outbound brochure.pdf

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The only Vans RV aircraft (other than the RV3 / RV12) that will fit due stall speed at 760kg will be the RV9 series. All the rest have published stall speeds greater than 45kts.

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14 hours ago, jetjr said:

CASA words not mine

Wouldn't VG constitute a change? 

 

Actually they are not CASA's words - Australian Flying Magazine got it wrong. At least CASA knows that a PA-22 is not a Tomahawk. The magazine introduced IAS but CASA just stated stall speed of 45 kts per the CAO so I guess they haven't yet worked out if it is supposed to be IAS or CAS.

 

The STCs for VGs on little aeroplanes generally don't come with a POH supplement showing the lower stall speeds and performance per https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20001212X20122&key=1 so officially the stall speed has not changed.

 

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For our purposes where the momentum is the issue the actual ie TAS on a standard day would be the only appropriate application.. Getting back to using weight  all instances of runway limits and terrain or obstacle clearance limits require a certain climb gradient be achieved apply weight limitations to achieve the required performance criteria. Ie you reduce the weight you operate at to achieve the performance. This is the proven, entirely safe and practical method. and is done on a situation to situation basis by the pilot. Surely it can be an overall application on a type. You don't alter the 45 knot rule you COMPLY with it. Anytime you increase the mass or load the wings must lift, you UP the stall speed . Similarly when you limit the mass, you reduce it.. Nev

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Sent  an email to RAAus about the stall speed as my wee Colt is 50 kts. They got back to me pronto and said it caught them by surprise as well. They are following it up as it  is not what was meant to happen, confirming the conversations with M&M at the Gawler seminar a couple of months ago, saying all was progressing well.

Ken

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1 minute ago, Kenlsa said:

Sent  an email to RAAus about the stall speed as my wee Colt is 50 kts. They got back to me pronto and said it caught them by surprise as well. They are following it up as it  is not what was meant to happen, confirming the conversations with M&M at the Gawler seminar a couple of months ago, saying all was progressing well.

Ken

Ken

 

Are you saying your Colt is currently RAAus  registered with a stall speed over 45kts?  Ive seen a couple of Colts RAA registered, there was one for sale quite recently. Lovely aircraft, I'd be tempted to have one myself.

 

Is there any risk they'd take your Colt off the register? 

 

Alan

 

 

 

 

 

 

 

 

 

 

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Sounds a bit like the RPL medical reform  CASA - "Here is a change in medical requirements, have some of this" -  "AusRoads standard" ( so no change really).

 

MTOW change 'Here is an weight increase - have some of this " "45 knot stall remains" (so no change really)

 

ho hum..

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Alan,

My Colt is VH reg and I am recovering etc it at the moment with a view to reg as RAAus as I dont want to work under two systems. 

Ken

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3 hours ago, Kenlsa said:

Sent  an email to RAAus about the stall speed as my wee Colt is 50 kts. They got back to me pronto and said it caught them by surprise as well. They are following it up as it  is not what was meant to happen, confirming the conversations with M&M at the Gawler seminar a couple of months ago, saying all was progressing well.

Ken

Ken, are you saying that "M&M" were assuming there would be a removal of max stall speed with any weight increase?   Or they hadn't thought about the stall speed of 760kg MTOW aircraft? This could cause probs with some aircraft already on the RAAus Register.  Aircraft now limited to 600kg thus keeping stall speed around 45kts at that weight but will increase at the higher 760kg MTOW. The Colt is one along with the RV4 and probably others.

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8 minutes ago, ave8rr said:

Ken, are you saying that "M&M" were assuming there would be a removal of max stall speed with any weight increase?

Proves my point that people got fixated on the weight increase without considering the downstream issues, which is typical of human behavior in other forums such as Parliament. Would love a dollar for every time a politician has excused poor legislation with the phrase "unintended consequence".

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 You mean the "WE didn't think of that"  effect.? Just shoddy administration.  You can build much heavier plane without exceeding the 45 knots but any weight increase to an" existing" design will cause a stall  speed (as defined) increase. If the "margin" isn't there you are against the limit. It's also "with Flaps extended" so a flapless plane is more up against it. Nothing new there.

  In an open discussion of where we are going ALL matters should be considered but remember GA exists and the RAAus is /was different . If you want ALL that GA has why would you expect that to be available without the REQUIREMENTS of GA APPLYING?  It's a trade off isn't it? Nev

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Doesn't GA want all the parts made for aviation "type approved",

If the builder of an aircraft makes their own piece, for their particular type of aircraft. It would be expensive to get that "type approval".

Hence we have to have ,

Exemptions.

spacesailor

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If you want to get technical, makers can approve certain "organisations" to manufacture assemble and repair certain or ALL of their products Qantas at Charleville were approved from DeHaviland UK for these purposes..

  Spacey, I can't see how we can possibly get rid of exemptions.  Nev

Edited by facthunter

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ave8rr,

 

M&M said that they were going for an increase in stall speed all along, and that MAY bring in the need to do a conversion of some sort to satisfy casa. Looks like they have been blindsided. They are following this up.

 

I have made sure I filled out the casa discussion/survey and explained that at least my Colt needs the increase to be included. If ever there was an aircraft that should be classed as "recreational" it is the Colt.

 

to all that have a J200 you had best fill out the survey as you wont get to 700kg if it goes thru without the stall increase

Ken

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On 05/09/2019 at 5:51 PM, ave8rr said:

The only Vans RV aircraft (other than the RV3 / RV12) that will fit due stall speed at 760kg will be the RV9 series. All the rest have published stall speeds greater than 45kts.

 

Well, maybe.    VANS published info for 9/9A is for MTOW of 727 kgs up to 795 kgs - (registered mine as 795kg). For stalling speeds, VANS published numbers are 41.6 kts for 727 kgs, and 43.3 kts for 795 kgs - ( mine stalls at 43/44 KIAS... didn't work out CAS!).

 

So, my assumption from what's been discussed is that my RV9A fails to fit inside the 760 kg limit, and that rules it out, regardless of the fact it has Vso <45kts. It stays in GA for now because the individual owner, regardless of whether they built it under EXPERIMENTAL or not, cannot change the manufacturers numbers without themselves providing the afcts to backup their claims. Very few RV9As will fit under 760kg without having been built specifically for this purpose.

 

With regards to my Brumby 610, which currently has a Vso of approx 37kts (POH), at MTOW of 600kg - I'd guess that it would not exceed 45kts even if it was loaded up to 760kg MTOW.  However, it's unlikely that it will perform too well, and in any case, the manufacturer probably doesn't have, and isn't going to spend big dollars, on doing all the testing required to increase its' MTOW.   It would take quite a bit of work - and for what benefit?  If the intent is to fill both the seats with 120kg people, and then fill the fuel tanks to 135L - most aircraft would weight 375 kg BEW + 240 crew + 100 fuel + 20 bags = 735kg. Pretty close to the new limits!  I'd be very, very skeptical of it's takeoff and climb performance being anywhere near what it currently has. That means a lot of new performance figures would be required for the aircraft or the POH would be demonstrably incorrect and therefore, unusable.

 

Frankly, this 760 kg MTOW limit promise is one which CASA cannot in all seriousness contemplate, without it costing a heap of development time and money for the industry. IMHO, it's a mirage, floated to placate a few noisy birds in the industry.

 

happy days,

Edited by poteroo
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I don't know how many have actually taken the time to read the discussion paper, but page 7 says quite clearly that the stall speed is to remain unchanged IAW 95.55.

(cut and paste from page 7)

Stall speed and minimum useful load requirements

The proposed amendment to the MTOW limit would not change the limitations that presently apply to stall speeds or minimum useful load requirements.

 

Section 1.3 on pages 3/4 gives an overview of which aircraft meet the spec and those that fail because of stall speed.

 

Stall speed as written in 95.55 is below. Bear in mind that the Advisory Circular for LSA requirements use CALIBRATED airspeed to determine stall speed.

 

stall speed Vso is the stalling speed, or minimum steady flight speed, at which an aeroplane is controllable with:

(a)   wing flaps in the landing position; and

(b)   landing gear extended; and

(c)   engine idling with the throttle closed; and

(d)   centre of gravity in the most forward position; and

(e)   maximum take-off weight.

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