Maximizing Lycoming IO360 Climb Performance

Discussions specific to Lycoming engines

Moderators: Rick, Lance Murray

User avatar
CFIDave
5 Diamonds Member
5 Diamonds Member
Posts: 2678
Joined: Wed Nov 07, 2012 3:40 pm
First Name: Dave
Aircraft Type: OTHER
Aircraft Registration: N333GX
Airports: KJYO Leesburg VA
Has thanked: 231 times
Been thanked: 1473 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by CFIDave »

I can't over-emphasize how important it is to have the governor adjusted so you can obtain as close as possible to full 2700 RPM -- that's the only way to obtain the full 180 hp (at sea level).

I've flown many mis-adjusted DA40s with lower RPM limits, and then talked to owners who are convinced that lower RPM limits are better -- that it's somehow easier on the engine. This not only reduces the cruise climb potential of the aircraft, but is a safety hazard during takeoff, when you want to obtain as much altitude and airspeed ( = potential energy) as soon as possible in case the engine quits.
Epic Aircraft E1000 GX
Former DA40XLS, DA42-VI, and DA62 owner
ATP, CFI, CFI-I, MEI
User avatar
Rich
5 Diamonds Member
5 Diamonds Member
Posts: 4592
Joined: Mon Aug 30, 2010 12:40 pm
First Name: Rich
Aircraft Type: DA40
Aircraft Registration: N40XE
Airports: S39 Prineville OR
Has thanked: 145 times
Been thanked: 1180 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by Rich »

The Woodward governor I have has been subject to wear over time such that my max RPM had slowly come down to about 2650. It otherwise works fine. I'm in the process of adjusting the high-end stop to get that back up to the 2690 range. It appears half a turn of the adjusting screw is worth about 20 RPM.

As a side note, the safety-wiring of this screw is different than the usual approach, which is to keep a bolt/nut from backing off. But this screw you don't want turning either direction. There's little danger of this, as the screw is held tight in the fitting, plus there's the jam-nut.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
User avatar
Rich
5 Diamonds Member
5 Diamonds Member
Posts: 4592
Joined: Mon Aug 30, 2010 12:40 pm
First Name: Rich
Aircraft Type: DA40
Aircraft Registration: N40XE
Airports: S39 Prineville OR
Has thanked: 145 times
Been thanked: 1180 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by Rich »

Another wrinkle is to ensure the adjusting screw on the governor is the actual stop. The travel of the prop lever might hit its travel limit first. This is easily assured by adjusting the housing trap nuts where the cable passes through the left front engine baffle.

The engine now will hit 2700 RPM. But it will often oscillate between “beyond 2700” (where the VM1000 will blink at me) and 2690 RPM. I settle it down with the merest tweak of the prop lever.

Good enough. :D
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
User avatar
OriensFlight
3 Diamonds Member
3 Diamonds Member
Posts: 91
Joined: Thu Mar 15, 2018 2:59 pm
First Name: Hans
Aircraft Type: DA40
Aircraft Registration: N556LU
Airports: KHES
Has thanked: 85 times
Been thanked: 48 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by OriensFlight »

Hey, it's June, so time to re-animate this thread. I had an awesome West Coast adventure this weekend flying from STS-TRK-VGT-SGU-VGT-MRY-SAC-TRK-STS over four days. It was especially challenging from an ADM standpoint because temperatures in Las Vegas and St. George reached over 110º and Truckee's DA reached 8,900' on one of the days I landed there. (I may post some photos and videos of the trip when I have time.) Thanks to CFIDave for talking to me about the desert flying aspect. I chose to depart and arrive TRK early and late (complying with the noise-abatement curfew 10pm-7am) and then with ~10 gal less than full, to stay well below MGW.

During the run-up, here's the high-DA leaning procedure I used (thanks to my CFI Rob @ RAM). I'm curious of you use anything different.

- Taxi to run-up area, being extra careful to avoid rocks and dirt.
- Run-up engine to 2,300 RPM (instead of the typical 2,000 RPM).
- Then begin to lean until rise in RPM begins to stop, and note the position along the "M I X T U R E" markings. (The bottom of my lever settled between "T" & "U" at around 2,380 RPM.)
- Reduce to 2,000 RPM and continue normal run-up.
- On take-off check position of mixture control as previously noted.
- On climb-out I noticed the CHT temps going above 400º, but still well below 450º.
- Above 500' I enriched the mixture a little to improve cooling and to get the CHT back below 400º.

This procedure was fairly easy for me to remember and it seems to have worked well for Truckee and the hot places I visited. (TRK Tower was helpful to point out a number of lakes to the north where they like to have aircraft departing to the West climb to higher altitudes. I know it's probably to help with noise-abatement and facilitate arrivals and departures, but it's also a wide open area clear of obstructions to climb in wide turns. The fatal Cirrus SR20 accident on June 15th at TRK was very much on my mind as I considered the ADM.)
Hans
N556LU / 40.763 - 2007 DA40 XL G1000 w/WAAS, SVT, TAS & ADS-B @ RAM Aviation in Healdsburg, California
User avatar
arksat
3 Diamonds Member
3 Diamonds Member
Posts: 136
Joined: Fri Jul 22, 2016 6:13 am
First Name: Tosh
Aircraft Type: DA40
Aircraft Registration: N00000
Airports: KHWD
Has thanked: 427 times
Been thanked: 59 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by arksat »

Hans, thanks for sharing your procedure. One question - you leaned to 2380rpm on run-up, but during the take-off roll, I guess you had higher RPM with full throttle. I wondered if it makes the mixture too lean and maybe that's why your CHT got pretty high?

I usually follow the similar steps to yours at run-up, but one of my friends said he adjusts mixture to max RPM during take-off roll, which kinda makes sense to me but I don't feel easy to do.

I'm also curious how the other people do on Lycoming DA40.
Antoine
5 Diamonds Member
5 Diamonds Member
Posts: 2043
Joined: Fri Oct 15, 2010 11:00 pm
First Name: Antoine
Aircraft Type: OTHER
Aircraft Registration: N121AG
Airports: LSGG
Has thanked: 87 times
Been thanked: 220 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by Antoine »

Very nice thread, especially the initial post! Here’s my two cents from an ex DA40 pilot who has since moved on but still recalls trying to extract maximum performance in the Swiss Alps.
I have found out that the IO-360 is a very robust engine. Both of my DA 40s’ engines were subjected to thorough inspections by knowledgeable mechanics at the time of selling them, and both had as-new cylinder conditions despite being pushed in the climb and virtually never running full rich.
The most important thing I have learned is that it is not only OK but also desirable to run the engine reasonably hot in the climb! CHT target was 400 F in my case. Doing this with a very well sealed baffling system is a good way to extract as much power as the engine can possibly make.
The somewhat counterintuitive fact is that cooling performance is much better at 400 F then say 360. This is simply because cooling power is a function of the difference in temperature between the surface of the hot part and the ambient air. So you might struggle keeping the engine at 360, but you’ll find it surprisingly easy to shoot for 400 and not exceed that. The GFC 700 allows fine tuning of airspeed for this purpose.

Both of my DA40s ( a 2007 and 2008, with Powerflow) were very happy climbing at 90 KTAS (not IAS). This may not have always been the absolute best climb rate but I liked how CHTs behaved and the climb was very satisfying ( sorry can’t remember actual fpm).

I am glad that other people are advocating leaning for maximum power. I have always done that at my 2000 ft elevation home base. One has to simply accept that the full rich setting is for the situations where we really need all of this fuel flow- in many cases a little bit less fuel is much better: the engine delivers more power and does not suffer in anyway. Now that I am flying with a turbocharged engine, the game is completely different, and I wanted to say to my normally aspirated fellow pilots that many of the horror stories really relate to turbocharged engines only.

Two hints with regards to engine baffling: The NACA engine air inlet in the front is sealed to the lower cowling with rubber parts, it is important to make these sit perfectly and it might even be a good idea to actually add material to make a perfect seal - leaks in this area will cause high pressure in the lower part of the cowling, reducing the pumping effect.

It is also worth taking a look at how your oil radiator is seated and if it is really sealed to its cooling duct. In my first plane, the rubber seal was completely missing at this location!

Safe flying - I certainly miss my DA40 and am very grateful for the 1000 hours of pure joy!
User avatar
OriensFlight
3 Diamonds Member
3 Diamonds Member
Posts: 91
Joined: Thu Mar 15, 2018 2:59 pm
First Name: Hans
Aircraft Type: DA40
Aircraft Registration: N556LU
Airports: KHES
Has thanked: 85 times
Been thanked: 48 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by OriensFlight »

Thank you Antoine, and for still sharing your advice here. I find baffling somewhat baffling. ;-)

arksat, I chose not to fiddle with the mixture on the take-off roll, only keeping my hand near the lever and monitoring the CHT. Next time I’m on a suitably long runway with another pilot flying I may see if a slight adjustment will lead to better performance. Per Antoine’s guidance I may keep the CHT at 400° while in the climb.
Hans
N556LU / 40.763 - 2007 DA40 XL G1000 w/WAAS, SVT, TAS & ADS-B @ RAM Aviation in Healdsburg, California
User avatar
Lou
4 Diamonds Member
4 Diamonds Member
Posts: 370
Joined: Sat Nov 21, 2015 1:39 pm
First Name: Louis
Aircraft Type: DA40
Aircraft Registration: CGXLO
Airports: CZVL
Has thanked: 118 times
Been thanked: 115 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by Lou »

Good discussion.

I noticed this comment in the Deakin article:

“ One short cycle of the prop with a 100 or 200 RPM drop is sufficient to indicate proper functioning, and further (or deeper) cycling accomplishes nothing, unless it’s very cold outside, and the prop is sluggish.”

The folk wisdom of the northern pilots is that you should not deep cycle the prop in cold weather. Apparently the seals get stiff and can easily fail. It’s folk wisdom, so I don’t know if it’s true. I am more cautious now.
User avatar
Colin
5 Diamonds Member
5 Diamonds Member
Posts: 2006
Joined: Sat Aug 21, 2010 8:37 pm
First Name: Colin
Aircraft Type: DA42
Aircraft Registration: N972RD
Airports: KFHR
Has thanked: 319 times
Been thanked: 527 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by Colin »

After flying with Deakin I stopped cycling the prop on my DA40. I think I did it once a month with my VOR check (no longer needed after my WAAS upgrade).
Colin Summers, PP Multi-Engine IFR, ~3,000hrs
colin@mightycheese.com * send email rather than PM
http://www.flyingsummers.com
N972RD DA42 G1000 2.0 s/n 42.AC100 (sold!)
N971RD DA40 G1000 s/n 40.508 (traded)
User avatar
Tim H
4 Diamonds Member
4 Diamonds Member
Posts: 453
Joined: Wed Dec 29, 2010 3:44 pm
First Name: Tim
Aircraft Type: DA40
Aircraft Registration: N233MA
Airports: KMGY
Been thanked: 34 times

Re: Maximizing Lycoming IO360 Climb Performance

Post by Tim H »

This thread has got me thinking about takeoff performance.

I've been watching my takeoff RPM and it seems to be low ~2620 as I begin my takeoff roll. I mentioned it to my mechanic and asked him to bump it up to ~2700. He said the adjustment is already at the max RPM and asked if the RPM was always low or if this was a recent development. So, I looked at my engine logs going back to 2011 (the RPM data is taken at 60 kts IAS) :

6/17/2011 2633
7/26/2013 2639
1/21/2017 2684
8/2/2017 2648
9/15/2020 2623
12/2/2020 2645
2/25/2021 2675
4/18/2021 2655
10/5/2021 2632

One thing I noticed is the RPM seems to be higher in colder temps. Does the temp impact max RPM and if so if the prop is adjusted in cold weather then it won't make max RPM in warm weather and if its adjusted in warm weather then it might overspeed in cold weather?

Is it time for a governor overhaul since the adjustment is at the max RPM and I'm not making max RPM?
Post Reply